Bad billing

I have an account with identity as from last year, and I've been paying it monthly i didn't skip any payment. This month i paid on the 06/05/2021.i paid an amount of 370 at nhlazatshe in mpumalanga. To my surprise i got sms's saying that my account is in areas and i will be handed over. I called the head office and they said that the payment doesn't reflect on their system. I tried to explain that i did pay and i even faxed the slip as proof of payment, but still the calls were coming. I had to drive 110km to the store to enquire. And they said the amount went to the wrong account and it will take 2 to 3 days to be resolved. Now this has reflected negatively on my credit report as now it appears that i skip payment. And what pains me is the fact that no one from the store is admitting an error or a mistake on their side and seemingly they don't care about how this thing will affect my credit record. I deeply hurt about this and worse i know the calls are charging on me as well.