Contact never cancelled

I have had my contact cancelled with Cellc from. Last year October. I've never used their phone, they came to collect their devices but yet I have to be paying for something that I've never used. Tried to contact their customer care with no assistance, the last consultant I spoke on Wednesday said my contact has been cancelled and to my surprise I then recieve a messages that my account has been handed over to SSDA. CELL C IS THE WORST SERVICE PROVIDER 😡