PATHETIC SERVICE MBD

I have paid MBD for 5months each and every month as per the agreement that was made with me over a phone call to settle my standard bank cheque account I was paying every month without fail only to get a call about 5 months later from another firm saying my account has now been sold to them and they handling my account I paid MBD ATTORNEYS I have been trying to get hold of them to pay my funds over to the new law firm I have sent proof of payments to MBD that I have paid them my FNB bank has confirmed this account belongs to MBD they also habe that from me so what more must I do to get my funds allocated to the account so I can settle my account

I need urgent assistance with this matter please