2001 Chevy S-10 Timing chain

Ok I had a timing chain go out, snap explode or break. I sent it into a shop they told me it was gonna be $800 to fix, ended up being $762. That was great! However they didnt change the oil or filter, I picked the truckup it sounded great! Drive it 60ish miles, now Im lost oil pressure and clunking sound internal within the motor! So now I take it back to shop. The tell me my motor is shot. SO Icalled around found out that this actually should have only cost $388ish. SO now im in a fight with the owner of the shop, However he states he did by accident over charge me by $250. But now my truck is dead, I little bird told me that the shop has pulled my motor and pulled the oil pan to find debris, and the main bearings are HOSED along with the CAM. SO now what do I do? The shop is now stating that that this problem happend when the timing chain went out. Even though they found debris in the housing they are stating its not there fault, is that true? Any Suggestions, (The shop did also go and get bearings and a rod to replace if needed) but now that this is found Donno what should do. Any HELP Would be GREAT!