Loan account direct payment

I have a personal loan which has arrears, debt collection company made contact that the account has been handed over which surprised me as to why did Absa not warn me first about the hand over. I then advised that I have had financial difficulties but I now have some steady income although it won't be enough to pay off the arrears at one go I can only afford to pay R800 per month, which then just before August I received an sms reminding me to pay the R800. I paid it end of August directly to the loan account, and ever since I have been paying the R800.. Today as I try to pay with the extra amount I have the deposit got rejected with error code 57 "transaction not allowed". Now I'm left confused are my payments now nolonger allowed? Have the previous payments been allocated to the loan account!? I have been trying to get through the contact centre but to no avail. Can someone explain to me where is my loan account, I want to pay it still with little that I have till it is settled but I'm unsettled now as to whether my payments were allocated and why could I not deposit today.