Standard Bank Not Cancelling my bond account.

on the 27th June 2015 i received an offer to purchase my property, on the 15th July 2015 i sent through the signed bond cancellation forms to NGL Law attorneys, on the same day i sent through my existing bond details to the NGL Attorneys. on the 18th August 2015 i got an email from Nicole from NGL attorneys advising me that there's a shortfall of approximately R70000. I then responded by saying i'm willing to sign an acknowledgement of debt to pay the shortfall amount in installments. they told me they contacted the cancellation department and waiting for response. this never happened, until today we still don't have answer from the bank, every time the attorney's make a follow up, they get sent from one person to another, and i also made a lot of calls to standard bank, and no one has assisted me, i get sent from one person to another. i spoke to Thomas Smeers, Portia Mbhele, Bianca, Nomsa and a lot of other people, and no one has managed to let me know what's going on or what it's the hold up, it's been five months now, and the seller is threatening to back out of the deal now. can someone please assist me with this query. my bond ***.