premature quote

Good day,

I opened a contract with MTN August 2020 which I pay R579. I have 17 months o my contract when i calculate the penalty fee its about R9800, with no discount as goes for my laptop contract. my Father took out the same contract with a different provider and his penalty is far less and his getting a discount. MTN retentions informs me that instead of giving me a discount they adding 15% because of early termination. I asked to speak to a tl they dropped the call after holding on for 40mins

kindly assist

Thank you,