DO NOT FILL AT BP !!!!!

So I have a 2006 CDI (diesel) in good condition. Our dear BP on Grovenor Crossing has filled my car with petrol, they admitted liability took the car to Mercedes for repair and dealt with Mercedes. The costs to repair are over 68k, now their insurance wants to s**** my vehicle for 70k, or pay me 46 to fix it if I keep the vehicle. How am I supposed to replace the car on 70k

I have spent alot on Uber for the past 6 weeks and have been given the run around. BP has passed the buck and are so deceptively being quiet. So to all reading this. Do not fill you vehicle at BP Grovenor crossing and avoid BP if you can. They have zero honour after admitting liability and promising to fix it, it was just a ruse.