2007 c230 Brake lights out, no radio, fuel gauge, headlights turn on strangly
 

I think someone hooked the battery up backward and shorted something out. I had the battery changed and I remember the guy seeming to 'low level'' flip out when he connected the positive cable. After that, a bunch of stuff just stopped working, brake lights, fuel gauge, rear head rests, rear window sun blocker, radio and navigation, fob works to lock and unlock if the fob is literally touching the door sensor when pressing the buttons. The interior curtasy lights when doors open are not working. I changed the rear SAM module which helped a couple other issues I had like my seat heaters turned off after every 30 seconds since I purchased the car and the rear SAM Module fixed the seat heater issue as well as a couple flashing dash lights. I also replaced the headlight switch since they are 'all or nothing' now. Meaning they're either off or turn the Headlight switch all clicks to the right and then ALL the headlights/park lights power on all at once. Anyone know whats left that could be 'blown'? Thanks for reading and any help.