paying double payments for a certain month

My account was up to date yet they said i owed June 2015 payment. I had proof that i payed for June 2015. In October 2015 they kept on suspending my account, but found out that they didnt receive June 2015 payment. I send through the proof of payment but they demanded that i pay again for June 2015 otherwise they cant reconnect me. So i made the payment and they said that they ware going to refund me the amount but failed to do so. Why must i pay double and dont get my money back. And nobody seems able to help me.