FNB Joint bond with Ex Spouse

I am a divorcee having a FNB joint bond of the property with my ex spouse. This property was purchased and bonded with FNB as joint bond when were married. We are divorced now and as per the divorce documents I must take over the ownership of the property(FNB joint bond property) and get new bond to be registered under my name only. This new bond will be with different bank as they are giving me a better interest rate compared with FNB.

FNB is refusing to cancel the joint bond that is registered under my name and ex spouse because my ex spouse is not providing the proof of address to FNB. FNB is provided with all the divorce documents together with the signed FNB Bond cancellation form and ID copies of myself and ex spouse. FNB is not cancelling the joint bond as my ex spouse is not giving them her latest proof of address.