over charged by DSTV

I received a call from a very polite lady from DSTV this morning. She told me that they over charged me with R112.66 and she asked if I would like a refund or if the amount should be deducted from my next debit order which is on the 1 November 2023. I requested her to deduct it from my next debit order. I have a price lock at R839 monthly for DSTV. If they deduct the R112.66 from my debit order of R839, the new debit order should be R726.34, but my new debit order shows R791.34 which is wrong. There is still a R65 extra that they are over charging me. I would appreciate it if they can rectify this problem.