Sounds to me like they need to read, AND UNDERSTAND, the instructions. Do they have a set of Volvo service manuals? If not, and they haven't worked on a 960 engine before, its very likely they screwed up!

Crankshafts don't break.

It reads as if they didn't install the timing belt properly and the belt came off, causing the valves and the pistons to collide. Bent valves means either a new head or a repair job. Some of us here know from another posters experience this is not an easy thing to do.

The head is a three piece affair, with all sections glued and bolted together. Complete replacement is preferable.

Please get more details.

First of all, I want the name and location of that dealer so I can stay clear of it. Secod I would push them real hard about your concern of cometence and replacng the engine. Perhaps call the district manager. Abe or other service managers mght be able to advise you here. I do know that the only replacement specified in the TBs is a newer style engine. It may be worth your while to see what it would cost additionally (if any) to have them drop one of those in, instead of messing with your old one that has 90K on it.

Whatever your inclination, be relentless until you are satisfied.

Sounds as though they owe you a major rebuild, since they screwed up the timing belt job.

you did not say which belts came off, the fan belts or the timing belt? Was the cam shaft messed up or was the crankshaft messed up? If the 90,000 service included replacing the timing belt, it is possible that someone forgot to tighten the bolt that holds the timing pulley on to the end of the crankshaft. If not properly tightened, the bolt will come completely out and allow the pully to come off the end of the crankshaft. This can also cause the timing belt pulley (on the crankshaft) to come loose. If this occurred, look at the inside of the timing pulley. It will be rounded. There may be spalling on the end of the crank shaft as well.