Paid Twice by mistake, they refuse to acknowledge I am in credit only that they have received 2 payments!

In July I made 2 payments by mistake for my rental. I have been able to get acknowledgement from Audrey Shabangu in the form of the mail reply below - "Yes you have paid twice … both payments does reflect and yoy not on debit order you paid via EFT." However! They are refusing to acknowledge that I do not need to pay this month as I am in credit! I have sent multiple mails and am not having any joy! I mean how difficult is it to confirm this????? Communication from this company is ********** and I will never use their services again after this!