Transmission stuck and now won't start.

Hi,
I have a 1961 f100 ford pickup. It has a chevy small block 350 with chevy transmission. I had problems with it and got my mechanic to do a rebuild and check the transmission because it was getting stuck. Went to get it back and drove out of shop, and was driving really well for about 5 mins then transmission wouldn't get out of 1st (it is a 3 speed). Limped back to shop when the pickup stopped completely and wouldn't start again. They replaced the fuel pump in the rebuild. It is now back in the shop. I got plenty of apologises from the owner and mechanic. Am a little annoyed but understand that things with a lot of age can have multiple problems. Just wanted another opinion of what could be happening. These are the same problems I was having before I took it to my mechanic. And now seems to be happening again. Am I getting taken for a ride or is there something that my mechanic could of easily missed. He told me the last few days while they were tuning etc that all test drives went really well. Maybe I'm bad luck.