Unauthorized debit order

I had a bad experience with MTN, I had a contract of data with MTN and i was paying R99 , in April 2022 they increased my monthly payment before it can reach the annuity to R103.95, my contract was ending in August 2022, and I called in July to cancel my contract before its end and I got an SMS that says "Yello customer! your order has been submitted with order ref no: 1- *** thank you for using MTN" today on 22 of September I see a debit order of R174.80

Please call *** to resolve My name is Secilia