Incorrect balance

Woolworths handed over an account to MBD attorneys reference number ********** ********** 70 for an amount of R3000. I made a payment of R500 prior to the handover on 14 October and have sent numerous Proof of payments on this account yet the payment has not been allocated by MBD as yet. The balance is now R3256 and that R500 still hasnt been allocated. Instead i am dealing with very rude and sarcastic call centre staff each time they call me for collections. I called this morning again to find out if payments have been allcoated and im told that there the account is not allocated, but i should pay. WHY must I pay and yet they dont allocate the payment before handover? I made another payment yesterday.

Please sort this out as i am extremely frustrated with your service.

thanks