Wrongfull billing

Some months back my contract expired and I did not renew or upgrade. I called and requested that the contract be cancelled as I was not using the phone. Eventually the account was suspended. Surprisingly I kept on being billed for an expired and suspended account. This definitely is unfair customer treatment and I would not encourage anyone to deal with Cell C. I then called again their 084180 number and was never answered- which means this line is not being manned, the reason for this being that it worsts their time to attend to queries as opposed to getting more customers they can ***** money from. I then called their *** which apparently is for new contracts and upgrades- it was answered without much ado but was given the run around. Firstly spoke to Nontandana who could not help then passed me on to Matsikiso who also was of no assistance and I was passed on to Mitchell and then finally I was referred another lady called Nadia who then told me that the only assistance she could give me was to cancel the contract and referred to another number to question continued billing. Part of the monthly payments goes to buying the phone? why pay monthly after expiry and suspension