Bad service

REF *** Earlier this year I had a problem with being incorrectly charged for a data contract, after many phone calls the problem was sorted out and i was promised a credit onto my account. Tis was done on then 8-9-2023 R 399.50and 17-10-2023. R 394.90 and on my statement for November i as shown as up to date and only R105.05 due on the 30-11-2023. on the 19-11-2023 i received a message from collections saying my account is overdue with R925.75. This is not acceptable Notification I***-0. I do not have the time to sit for hours on the phone like last time so if this is not sorted out before the end of the month I will hand this over to my lawyers.