I took my car to garage to have waterpump and timing belt put on, garage put stuff on called me said cam seal was leaking and it

I told him no I didn't want to spend the money for that procedure so they put together ran it in garage I heard squealing like serpentine belt was slipping but it went away shortly then they took car out drove around block brought it back and parked it on hill and went inside so we went in and paid, I went out went to start it and it started and died so I looked at fuel and it was at empty so I let it roll back on street to see if fuel would change well went to crank it over and it started to then went dead, long story short pushed it back over to garage they came out open hood serpentine belt had shred wrapping around crank causing engine to skip timing and destroyed engine. The guy is saying he is not responsible cause he done job I asked him to do, well he didn't inform me of bad belt