I'm am trying to replace the fuel filter and i can not get it loosened for the life of me. any advice?

I REPLACED THE FUEL FILTER ON MY 1996 GMC JIMMY THE OTHER DAY. THE FILTER IS LOCATED UNDERNEATH THE DRIVERS SIDE INSIDE PART OF THE CHASIE.1ST DISCONNECT THE POSITIVE SIDE OF BATTERY, TO PREVENT ANY ACCIDENTS. THEN YOU JACK UP FRONT LEFT SIDE AND SECURE WITH JACK STAND.WEAR SAFETY GOGGLES BEFORE GOING UNDER NEATH THE VEHICLE. YOU WILL NEED THE FOLLOWING TOOLS; 20m,16m, and 13m OPEN END WRENCHES.TO BEGIN HAVE SOMETHING TO CATCH A LITTLE OF FUEL THAT WILL DRAIN WHEN YOU LOOSEN THE FUEL LINES.WHEN YOU LOCATED THE FUEL FILTER, TAKE THE 20m OPEN END WRENCH AND PLACE ON THE NUT FROM THE FILTER,THEN YOU TAKE THE 16m OPEN END WRENCH AND PLACE IT ON THE NUT FROM THE FUEL LINE THAT CONNECTS TO THE FILTER. BY HOLDING THE 20m WRENCH FIRM YOU REMOVE THE FUEL LINE NUT ON BOTH SIDES OF THE FILTER AS YOU LOOSEN THE NUTS FUEL WILL START DRIPPING FROM BOTH SIDES GIVE IT A MINUTE OR TWO .THE MOST THAT COMES OUT OF THE LINE WILL BE LESS THAN A CUP.NOW THAT YOU HAVE LOOSEN BOTH SIDES OF THE FILTER THERE IS A STRAP THAT SECURES THE FILTER JUST ABOVE THE FILTER,THERE IS A NUT THAT HOLDS THE STRAP YOU NEED TO GET A 13m SOCKET WITH A EXTENSION TO RATCHET AND REMOVE IT.LAST STEP FOLLOW THE FUEL LINE THAT GOES FROM THE FUEL FILTER TOWARDS THE ENGINE. THE FIRST CLAMP THAT YOU SEE HOLDING DOWN THE FUEL LINE TAKE THE 13m SOCKET AND REMOVE THE BOLT THAT HOLDS THE CLAMP NOW YOU CAN SLIDE THE FUEL LINE FROM THE FILTER.REMOVE THE FILTER AND BE CAREFUL THERE IS FUEL IN THE FILTER. TO REPLACE WITH NEW FILTER. REMEMBER TO LOOK AT THE ARROWS FLOW GO TOWARDS THE ENGINE