Unfair customer treatment - ABSA Home Loan

I have a joint bond with ABSA. Sadly after my partner passed away the account was in arrears due to his estate dispute with the executor. We reached an agreement with the executor regarding the bond that I should take over the deceased 50% portion. I have since cleared the arrears and trying to keep up to date with the monthly payment while I apply for finance of the outstanding balance but the monthly instalments are now twice as high from what we use to pay initially. I have contacted the bank on numerous occasions requesting a readjustment of the monthly installment but I'm being sent from pillar to post. This is becoming difficult for me to keep up with the re-payments. Can someone please look into this matter urgently?