Account debited

FNB appointed Brooks attorneys to do collections for credit card and i have payment arrangement with which i have been paying. January 2015 i defaulted and i contacted them to arrange a double payment for end of Feb 2015 and Brooks attorneys accepted. on the 25 Feb 2015 FNB card collection deducted R4780.00 out of my account and demanded i must get a letter from Brooks attorneys proofing that i have been paying before they can refund me which brooks attorneys refused to issue the letter. I emailed FNB card collections with all the proof of payments and still my money is nt reversed by FNB.