Poor Service from MBD Attorneys

I have an account with Woolworth,after losing my job 2015,Woolworth handed my account over to MBD,I had an arrangement in place in 2016 with MBD to pay my account,same years in September a consultant from MBD called me to,she offered me a settlement discount of if I pay the account before October 2016,I then made debit order arrangement with MBD take R889 on the 25 October to pay towards my settlement,a year later I got sms from the same attorneys claiming that I owe Woolworth ,they are taking advantage that I did not get payout letter from them.