The debit me R500 for my contract is finish and **** me something I didn't know my contract is finished why you debit me without my permission

I took cellphone contract 2021 after 24 months I call to cancel contract there suspend SIM card and cancel contract and then after 3 months they start to debit R500 on my account I reverse because I didn't know is for what.. when I sent email they didn't explain is for what they saying is error but the repeat even I blocked they change reference still now the try to debit me R700 now since my contract finish 2023 I reverse every month and my credit profile is on due from Telkom they **** me something I don't know is for what 😭😭😭