1999 Chevy Tahoe Would not start

Drove vehicle about 40 miles. Parked and picked my son up from school. Restarted vehicle and drove another 20 miles. Parked vehicle and was there for about 1 hour 15 minutes. Went out to start the vehicle and it sounded like it wanted to start, but would not. Next day I had it towed to a shop and they said it needed a tune up and that it had good gas pressure, etc. Also had a blower motor replaced as it had been on the fritz for a few months. Tank has a little over a half tank of gas when I started the adventure that day and was over 1/4 when I could not get it started. The shop did the tune up and didn't have a problem starting the vehicle to move it in and out of the garage and today they were installing the blower motor and guess what. It wouldn't start again. Now they think that it was my fuel pump all along. I had the fuel pump replaced in 2004 on this vehicle. What do you think? I am already up to $680.00 w/o the fuel pump. For a tune up and installation of the blower motor.