The car is not passing enough gas to and it makes my car buckle

If they pulled the dash then possible they removed the seats and stretched the wires or left them disconnected
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When you said it feels like its not getting enough gas, you may be right.
Since you have replaced the fuel filter, and you are not getting a check engine light, my suggestion would be to check fuel pressure with a gauge. The fuel pump may be weak.

The first step here and on any car with an air bag light is is to have the computer scanned to get codes out.
The computer will store a code when it detects a problem with the system, the code will help to locate what part of the air bag system has failed. for example there could be a code that reads b1234 pass/side buckle circuit fault, this code would tell us the problem is in the passenger side seat belt buckle, then with some testing the problem would be found. start by having the codes read, record and write back with codes , also including year,make ,model. good day

Did you transport a box or heavy object on the passenger seat?
The weight sensor (part of air bag system) detect a heavy object on the passenger seat.


With key on and engine running,clear the passenger seat ////// buckle then un-unbuckle to clear warning.

Also check the weight sensor and buckle connector.
Car wash clean can accident disconnect (or damage) this connector during vacuum.
======== Also inspect the pass. buckle opening for dirt.

ipersonaly i would look inside of the gas tank and make sure that the fuel pump didnt come out of place or out of the basket that is mounted to the bottom of the gas tank

The rear seatbelt of the forester was a bit of a puzzle for me as well when we first got ours. The buckle is really in two parts. The first part anchors the strap, and the second part secures the occupant.

Check if your belt is fully retracted, look in the inertia reel housing at the roof in the boot of the vehicle. Remove it passing the end through the 'loop' in the backrest Make sure that you have the two buckle parts I referred to earlier. There should be an odd looking buckle fixed at the end of the belt, and the more familiar buckle that slides up and down the belt. The end buckle goes into the receptacle vertically below the loop between the centre and window passenger and achors the belt in place. This buckle should not be normally released once used regularly. Once the centre passenger is in place, use the sliding buckle as you would for any other seatbelt and fasten on the receptacle on the other side to secure.

Use same procedure for fixing a car seat or booster, etc.

As far as I know that seat belt warning chime and light is there for your safety and protection, it should not be bypassed in any way.
There is no by pass seqwuence or code to eliminate this safety device.
Buckle up, its the law.

there is a switch under the seat feel arround under the seat and look for wires follow them up and down and find the plug it is likely near the carpet

YES THERE SHOULD BE A VACCUM WHEN THE CAR HAS RAN LONG ENOUGH JUST PULL THE VACCUM LINE TO SEE MAKE SURE THAT YOUR GAS CAP IS TIGHT