Incorrect billing - Affecting my credit rating

Incorrect billing - Query is still not resolved after receiving emails from Vodacom promising that they refunded my account.

1st email received from Vodacom Good Day! I hope this email finds you well. I acknowledge receipt of your billing enquiry. I have passed a credit of R820 for the incorrect billing of the fibre service, we apologize for the inconvenienced caused. I trust the above is in order. This service request will now be closed. Many Thanks and Kind Regards, Peter Ganca Vodacom FTTH Support ***

2nd Email: Dear Rene Bouwers Please note that an account statement has been emailed to you which reflect the account has been credited for July invoice with R719.23 on the 23rd August and R23.97 on the 1st August due to the migration for 50 Mbps price plan for R699 which took effect on the 1st July 2022 which reflect on the August 2022 invoice. Due to the return debit order in August the account was credited with the Return debit order fee of R100.88. We would like to apologize for any delay in this regard. Kind Regards, Hafiza Sydow FTTH Team ***