Cancel WIFI Contract

in April 2020 I went into a MTN store to cancel my MTN WIFI contract, they assist me by phoning from there MTN phone, as I do not have MTN number and you stay on line for more that 45min and still no answer. in May I had to phone again still the contract was not canceled they told me that June will be the last payment going of my account and contract will be canceled REF number ***. On the 15 July I send another may as I got invoice telling me a payment will go off the 25 July 2020, no one came back to me. on the 18 Aug I send another mail to cancel my contract and still its not canceled. today the 27 Aug still not canceled as another debit order went of my account. I need this to be canceled and need to be refund all the months. ( I have proof of mails I send Them)