engine locked up

like so many keep telling you. get it to a reputable shop and quit horsing around with these backwoods oil changers

 

then I would not accept anything less than a engine that has been rebuilt and put on a dino and tested.

 

Are they refusing to pay for it?

 

That's actually kind of good news. That means they're admitting fault. That makes everything else easier. But you still might need to hire an attorney.

It would be best to have Detroit rebuild it, and have the shop at fault pay the bill. They're liable for the damage, and nobody says you have to let them fix it.

 

Their budget doesn't matter. Call a lawyer.

And call the Detroit shop. Ask them if they've dealt with this before, and what the outcome was.