1998 Isuzu Rodeo Question Should I listen to the dealership?

After not using my Isuzu Rodeo for two years and leaving it outside in my parking lot, I decided this week to get it fixed because the engine doesn't start anymore. I sent my car to the dealership wanting to replace the fuel pump, because an expert two years ago told me that my fuel pump is why my engine won't start -- and nothing else. The dealership said they would charge me $357 for the fuel pump and $145 for the labor. I said, "Okay, " and that was it.

However, the next day they call me and tell me that my engine computer needs to be reprogrammed and all the fuel inside needs to be drained. I thought about this and asked a few people online about their thoughts on the matter. Some people said I didn't need to have my engine computer reprogrammed.

The dealership added that it would cost $210 in labor fees (without any parts, just labor) to reprogram the engine computer and drain the fuel in the tank and pipes. I said, "Okay, but that's all, right?" He assured me it was.

Then, today, he calls me and says the engine computer is REALLY bad (he emphasized REALLY) and I need to buy a new computer engine. The dealership said a new engine computer will cost me $400.00, but they found one that's five years old and costs $120. I recorded all our conversations as evidence just in case anything went wrong.

I feel like I'm being had. They keep piling up the prices. They have already charged me $210 for the labor of reprogramming the engine computer and draining the fuel, now they want me to buy a whole new engine computer.

What should I do?