1977 Other Volkswagen Models fuel pump

I just bought a 1977 volkswagon van. The engine was rebuilt 5 years ago and has about 8000 miles on it. I drove it home with no complications and the next morning I tried to start it up and it wouldnt turn over. It sounded and smelled like the gas wasnt getting through. I put 3 gallons of gas in it, jumped it, and tried to push start it with no luck. I towed it to a mechanic, described the problem and told him that I thought it might be the fuel pump. A $500 tune up (new filters, wires, spark plugs, ildle adjustment, NO new fuel pump) later, I drove it home. Again the next morning it did not start and it sounds like the same problem. I am towing it back to the same mechanic (evne though I dont trust him) to hopefully fix the same problem again. Is there anything I can do to save myself a $500 bill?