WORST EVER SERVICE FROM MTN AND MONDO!!!!

I app**** for a phone online with Mondo they delivered the phone and i took it back to MTN because it was not the phone that i wanted.

1. So MTN started debiting the actual monthly premium which was R500+ it was in August and September 2021.

2. So I received I received an sms confirming the cancellation of the contract and I was advised that the premiums will be refunded back to me which was not done

3. MTN has now being debiting the full contract amount which is around R17 955 and in this case the debit order keeps bouncing as I don't have that amount in my account which is now affecting credit score, risk profile and I have to pay for the bounced debit orders

Its now affecting my chances of being approved for any credit.