Cell C Charges Frustration

As a long-time subscriber of Cell C, I have faced multiple issues with them over the years. Recently, I upgraded my cellphone online and then cancelled the device, requesting it to be collected as I changed my mind. Despite the device being collected, I am still being charged for it. I have tried to resolve this issue by contacting customer care several times, but to no avail. The promised response within 2 working days has not materialised even after two weeks. I have also visited the Cavendish Square (Cape Town) store thrice, with employees promising to call me back, but I have not heard anything.

I am extremely frustrated with Cell C's disorganisation and do not know what other actions to take.