Cell C contract is a ****.

I paid off my 24 Months contract with them, then later send an email for them cancel the contract, i got a response saying they will get back to me till this day im being billed on monthly basis, i had their call centre agent telling me they cant cancel the contract before i pay for the months billed as it was my responsibility to cancel the contract. i told the agent that ive send an email and it got a response, so what more must i have done, she said i should have called instead of sending an email. now im stuck with a R1600 bill that i cancelled but got billed anyway, Cell C is a disappointment. lost my phone and they did nothing about it, since January no correspondence from them, i decided to let it go.