They don't want to process my refund!!

I was charged twice for the month of March after cancelling my service with rain. I logged this issue with them in April and they have been giving me the run around since then. One minute I am being told the issue has been escalated, the next they tell me it wasn't a duplicate charge it was a late payment (LIES!!!) and then it they said no this was a charge for April but I cancelled my service with them in March and then they said i must send my bank account so they can process the refund but it has been almost 3 months they have now resorted to ignoring my emails. I have sent bank statements as proof but they refuse to refund me. It's truly disheartening to watch a business play with your hard earned money like this.