Poor customer service

I had a contract with MTN SA which ended last year October and they kept on debiting my account for two Simcards which I didn't agree with them to debit that amount and I only agreed with them to be debited R650 for 24 months. When I call MTN customer service dropped calls on me, today 29th April 2024 a lady was busy talking to her friends while I'm on the line she later transfered me to Yanda at retentions who also dropped the call on me. MTN please investigate and help me cancel these non contractual debits