cell c refusing to cancel my account and charging me :-(

I have been trying to cancel my fibre contract since October. I have made numerous calls and received various reference nunbers. I was told my account would be cancelled and that I would have to pay for 1 month. but I've received another invoice indicating that I need to pay for three months when I've been asking to cancel since October 2020. this is unacceptable especially during this TOUGH TiMe where personally my salary is affected due to vivid 19. please cancel my contact. there had been no usage since OCTOBER AS NO-ONE EVEN RESIDES AT THAT ADDRESS. I was called and advised the person of be making the final payment asap but why am I still being billed when I've asked to close the account months ago already.