Wesbank commuting *****, Paying more then the agreement but not getting allocated.

My original debit order amount according to the amotorisation schedule my debit order amount is R2066.05 per month I have felt behind one month and they called me and I said to make the debit order R2500 till its up to date. on the 4th month they called me move it back to the original amount of R2066.05 so I said no to keep it at the R2500 then I know there is always extra paid and its paid off faster.

But the end date is saying the same and I called, I have been emailing them non stop but they do not get back to me. and this has been going on since August 2020

The first time I spoke to them they said it because I am in arrears. But I have my records stating that I have paid. they told me they will investigate but they do not get back to me