Displeased with service

Hi,I am very displeased with the service and the handling of my contract,allow me to explain,I had finished my 2 year contract and I was told that I was going on to a month to month contract and if I don't pay it will automatically cancel the existing contract, but just to find out that everything was not as it seems,they are debiting jy account and then I write back the monies,so to my frustration I decided to pay virgin active water meyer Pretoria to find out what's happening, just to be told that I am in arrears and for cancellation I new to pay that first,so my question is that,how do become in arrears when I was told,its a month to month contract and it cancels automatically if not paid,so I am being billed for something that I am not using.