misleading sales staff

I had a cellphone contract with Autopage. After the 24 months I assumed it would be the end of our relationship, but unfortunately things turned sour. My contract didn't end, instead they started billing me on a month-to-month basis, which I didn't pay. After failing to pay that 1st month they suspended my service, so again I thought now this is the end. Boy was I wrong! They kept sending me bills for each month, it went on for about 5 months, at which point I phoned them and asked them to stop it. At that time my bill have not yet exceeded R2000, but they didn't again sent me a bill, untill today, I got a bill stating I owe them Close to R6000 - what makes it worst is that they also blacklisted me.On top of that I've been suspended after the 1st month so they expect me to pay for services that I didn't receive!!! This is totally wrong! ****************! I didn't receive the BIS service nor did I receive the R200 monthly airtime, this is totally unacceptable!!! No one informed me right at the beginning that after 24 months they would automatically change the contract to a month-to-month thing.I feel betrayed!