MTN and Mondo refused to cancel the contract without a cancellation fee even though it happened within the cooling period

Basically these companies should be getting a zero on my rating. I bought a contract with MTN through Mondo and the data sim was not working after i bought their recommended wifi. I had to call them every hour for them to open the line so i could access inyernet and it will disconnect and never login until i call. I couldn't stamd this as i cancelled within the first 10 days but they still charged me the cancellation fee aftet debiting me for conmection amd usage for one month. I only managed to use their sim for less than 2 hours throughout the contract sunce i got it and xancelled. Till today im busy chasing after them and monfo to get my refund for cancellation fee that they refused to waive even though i was still within the cooling period as they demanded payment prior to the cancellation. I totally don't see a need to talk about cooling period if you are not going yo enforce your part of the deal and refuse to cancel without paying cancellation fee even though its still within the cooling off period. All i want is for you to refund me the same way you deboyed the account