I pried the back seat up but it doen't come loose.

I will assume that the seat release lever releases. You'll need two people one to hold down/pull out on the release lever the other to pry it out
you'll want a small block of 1/2-3/4 " wood or some protecting material to put down to protect the floor carpet... a pry bar or equivalent. there is a metal frame at the rear you'll be prying up and on.
Hope this helps
model make year would help me too?.

I assume it doesn't fold down. You will have to pry at it. Probably will damage the seat back doing this as they are designed not to come apart in an accident. A locksmith would probably be cheaper or even prying the trunk lid open...I'd call and find out how much the seat back is vs trunk lid before i did either.

You can try to pull on the belt with the plastic trim piece removed the take a flat tipped screwdriver the release the arm or bar holding the belt in the lock position. Most of these have a spring on them. That spring can fall out. Or sometimes the bar or lock arm may be jammed and needs to be pried loose then lubricated to prevent this from repeating in the future.

using a tire iron push up under the backseat bottom prying toward the trunk there are two large clips one on each side, The seat back comes off by prying it towards the headliner (top) of the car.

https://www.linkedine.com/pulse/how-replace-damaged-seat-belts-all-star-auto-solutions

NO NEED TO REMOVE WHOLE DASHBOARD!!! REMOVE TWO7MM SCREWS FROM THE BOTTOM OF STEERING PANEL & PRY AND REMOVE PANEL.
NEXT REMOVE TWO 7MM SCREWS ON BLACK PLASTIC STRIP THAT YOU SEE AFTER REMOVING STEERING PANEL....PRY THIS STRIP OF PLASTIC OUT JUST A LITTLE AND CUT IN THE MIDDLE .
NEXT REMOVE TWO 7MM SCREWS FROM AROUND TOP OF INSTRUMENT PANEL (BY GAUGES ) PRY PANEL STARTING FROM AROUND VENT ON LEFT BY DRIVERS DOOR ""THIS PANEL WILL STAY IN PLACE LOOSE... NO NEED TO REMOVE!""
NEXT YOU WILL SEE 0NE 7MM SCREW BY GEAR SELECTOR AREA.. BEHIND THE LOOSE PANEL REMOVE THIS SCREW.. ALSO IN SAME AREA BUT LOWER THERE IS ONE 7MM SCREW THAT NEEDS TO BE REMOVED THAT HOLDS LOWER DASH PAD ITS FOUND BEHIND LOWER CORNER OF DASH PAD.( LOWER DASH PAD GAS PEDAL AREA )
"DON'T"!!! REMOVE THE FOUR 10MM BOLTS!!!! IN SAME AREA
NEXT REMOVE RADIO /AC CONTROL TRIM WITH THIN SCREW DRIVER OR PANEL TOOL IT HELD IN BY SIX CLIPS...NO NEED TO DISCONNET ANYTHING IT WILL STAY THERE HANGING!!
NEXT REMOVE TWO CENTER CONSOLE LOWER LARGE PLASTIC CLIPS BY FLOOR MATS. NEXT UNDER SQUARE BLACK RUBBER AT CENTER CONSOLE REMOVE ONE SILVER SCREW. MOVE SEATS FOWARD AND REMOVE TWO 8MM SCREWS FROM SIDES OF CENTER CONSOLE FROM BACK SEAT.
PRY CUP PANEL SECTION THAT WAS HELD DOWN BY SILVER SCREW ...PRY UP TOP HALF OF CONSOLE STARTING FROM SECTION WHERE ARMREST DOOR IS.. DISCONNECT LIGHTER PLUG AND REMOVE PANEL .
NOW YOU WILL SEE SIX SCREWS STARTING FROM BELOW RADIO TRIM WORKING BACK TO ARMREST DOOR

Remove the wheel and the lower ball joint from the spindle. It will also make it easier if you remove the tie rod end. There is a large hut at the tire end of the axel. Remove that nut and washer. Take a rubber or brass Hammer and hit the end of the axel to push it through the bearing assembly. If it is really stuck, put the nut back on so that the nut is even with the end of the axel and uses a heavier hamer to break it loose. Once you break it loose, pull back on the rotor while pushing the axel to remove it from the hole it passes through. (Becarefull with the brake hose. If it is pulling too tight it might be best to remove the caliper and use a hanger to suspend it until you are done.) You will need a really BIG screw driver or a pry bar. Put the pry bar between the case and the hub of the axel and push in quickly and firmly to pop it out of the trans axel. It might take a few tries. If it resists look for a ridge and put a big screw drive on the ridge and use a hammer to pop it out.

Once it is out, reverse directions. Do not use the hammer on the new axel any where.put the end into the trans axel as far as it will go and then put the other end through the wheel bearing. Use the leverage you have with the rotor and bearing side to push the axel into the trans. You should hear it snap into place. Before you put the ball joint back on go to the trans axel side and use that pry bar and gently try to remove. if it resists it is seated, if it slides out, you need to seat it again. ONce you are sure it is firmly seated back into the trans, you can bump the ball joint and tie rod back together.

Good luck and be careful
Rich

place a crowbar under the seats near the carpet and, pry up gently the car has clips under both sides of the center seats then: push down on the top of the seat back disengaging it

My drivers side power seat stopped moving forward and back...back rest still worked. Took it to dealer and they charged me $60 to fix a "loose wire."
The seat worked for 2-3 days and quit again. Took it back to the dealer, and they now said it needed a new motor and track at a cost of $750+. Told them to forget it and called GM. GM will not cover it, and they have not covered a host of other problems like new radiator, new water pump, new instrument guage cluster, cracked exhaust manifold, and misaligned rear door/window air deflector (which they even have a bulletin out to all service department that it is poor design and the body shop should "shave the plastic down so it doesn't hit roof when door is open).

Back to the seat, I took a large, flat blade screwdriver and ran it along the seat guide rails and pryed on the seat mount slightly....guess what? It the power seat now moves forward and back.

Bottom line is GM manufactures junk and will not stand behind it. Now we know why the company is going bankrupt.

Just got my out. So, I thought I would tell everyone how to do this. First you have to remove the coat hooks, rear lights, handles and visors. My wife did these so thaey must be easy (just kidding babe). You don't have to remove the switches and lights up front. You will have to remove the wires later anyway. Now you have to remove the trim pieces at the A,B and C pillars. All these are attached with clips behind them. Use a long screwdriver (and cloth) to pry behind and loosen them. You will have to remove the seat belt on the B pillar. At this point you need to lay the back seats down and pop the three clips for the back speaker cover. Reach underneath and remove the wires. Slide the connectors off the clamp and unclip. This was a pain in the hands. Now the headliner is held on by a clip at the very back that I broke trying to get off. Also, there is velcro around the sunroof that you can use a long screwdriver to pry loose. At this point you unhook the wires for the front switches and it should be loose. Now comes the hard part. Bending the headliner to remove out the back door. I removed the neck support off th driver seat and moved all th way forward and up. I then really had to bend the headliner to remove. Lucky it is made out of a material the doesn't break easily. Good Luck.