Instrument cluster

I recently purchased a 2011 Malibu, the guy i purchased from had removed the original radio and attempted to put a new one in the told me when i bought it all he needed was a harness to connect the wires while doing that he turned on the anti theft so long so forth my car wouldn’t start took it into the shop to get it checked out because at this time I didn’t know it was on. Now my instrument cluster isn’t working or the gages are dead the lights still light up shows how many miles are on the car says i have low tire pressure and check engine light is on. I told the guy to trash the radio and try to put the replacement in. i’m worried he’s not taking me serious. Is this logical? this all stemmed from the guy I purchased the vehicle from was messing with the wires by the passenger side trying to get the power source to connect the radio