I'm sorry to hear you’ve had some problems with your energy provider. Switching is supposed to be straightforward, so it’s disappointing to hear about these issues.
To take this further, you can make a formal complaint to your supplier about how it’s handled your switch. You can do it directly, or via Resolver (a free and easy complaints site which MoneySavingExpert works with).
I hope this information helps and that you’re able to resolve these issues.