R30k over billing

I was under debt review and requested a settlement letter which I received and paid the quoted amount of R169,140.69 on Feb 26th. I registered on the African Bank website and viewed my account and the balance stated is R139,164.57. the settlement was R30 000 more than what the system shows. the call centre agent explained that because I settled my account earlier than the years of my contract, which in my book is a good thing, my balance was recalculated to that amount that is 30 000 more. <br> <br> the response does not make sense to me and I tried to get clarity but the more I ask the more confused I get and I am told if the bank owes me anything, they will recalculate and get back to me sometime in March.<br> maybe if I can get someone to explain the 30 000 difference to me?