How can i fix my vectra?

I ahave a 2003 Vauxhall Vectra 2.2 Dti SRI Deisal
the engine will not start (On dash board there is a car with a spanner in the middle of it) the engine immobilizer is engaged and have had to tow car home by RAC They think it could be injection pump but have no firm answers. Garage will not come to me to confirm problem they say scrape it but i only bought car 5 weeks ago drove 50miles to coast stop and walked about and then went back to car and could not start it