I'm being charged for No Service

I paid VOX in July but they suspended my account saying they couldn't locate the payment. I had to ask the bank to step in and investigate and still after sending proof of payment, VOX would still not activate my line. Till today, I'm being charged for this and they will not resolve this matter by investigating on their end. I am now indebted to VOX because they want double payment and are still sending invoices for each month while I have not being receiving any service from them. Worse still, they won't release my line.