Nedbank Business Banking - Not releasing sureties, cessions and gurantees

After having banked with Nedbank Business for nearly 10 years, we changed banks as a result of restructuring the business operations. In doing so, we sold a property that was being used as collateral for lending facilities. On transfer of the property all lending facilities were paid up to Nedbank, being the 27th April 2018., and Nedbank agreed to then release cession of debtors and personal guarantees on transfer. As of today, the 23rd May 2018, we still have not had the debtors cessions released, nor have the personal guarantees been released, and despite numerous phone calls and emails to our Business Banker, we have not been able to resolve this to our satisfaction. As a result we have not been able to negotiate new lending facilities with the bankers we have moved to which is now putting undue pressure on our cash flow. I can't understand what reasons Nedbank would want to have for dragging their feet in releasing the cessions and guarantees. It's not like they have made an effort to try and retain us as a customer.