renault trafic won't start?

02 renault trafic dci100 serviced by garage then didn't run as well. took it back to garage who renewed the fuel filter again and all seemed good, they said it was defective part.
the van has not been the same since. after occasionally spluttering and losing power it stopped shortly after starting and has not started since. won't prime the fuel filter and garage says needs 2 new injectors and possibly new hp pump maybe new engine!! surely not?