Cellc contract ***

I canceled my Cellc contract sim card on 19 August 2020 because my contract end in June 2020 then the lady that was assisting me was Sibongile she said I have to wait for 30 days for my account to be canceled then I waited then then they kept on deducting up until today I phoned then again this year 12 July 2021 they said they will cancel it with an immediate effect. I was shocked again if they deducted again on the 15 July and I'm surprised because they keep on sending me money that I must pay on the 15 of August this month I'm really disappointed about Cellc because it seems like I'll pay forever. I went to Durban Workshop cellc store they couldn't help me they said I must phone them myself if I phone they they're not assisting me and they said fault is with cellc I want my refund they're owing something like R3090.00