********** debit transations

I cancelled my rain per phone and they asked for an email, that state I cancel it for the end of August. Last month they took double money from my account. I phoned them again and spoke to someone. She asked me to send her my 1st cancellation letter, I did. She promise me that it has been cancelled. This month they take money again. My bank dont want to cancel the transactions and paid the money back to my account, according to my bank you can cancel your sim online - I cant find it anywhere!! At the end they cost me a lot of money for service that I dont use and has been cancelled. I want refund for the payments done after cancellation.