It would probably be best if you took the machine back to the shop, with the thread you're using and the fabric you're sewing on. Then show the tech what's happening. If you paid for a service, they should be willing to take the time to check what's happening, and help you fix the problem.
My first thought is that you may have missed a step when threading the top thread. When thread bunches on the bottom, it usually means the thread isn't in the top tension or the top tension is too loose.
Sewing with hand quilting thread can also be a culprit. And sewing with the needle in backwards...
When thread breaks, it often means there's a burr on the hook or the plastic bobbin basket is damaged.
The take-up lever rarely needs replaced. However, the timing could be off and the take-up could be pulling at the wrong time -- not in sinc with the needle or feed dogs. But that should have been fixed with the service.
I hope you can get back to sewing, soon.