Nedbank Home Loans' unclear and dubious practices

In 2017, while single, I registered a bond for a property in my name. I paid the monthly amounts every month from my personal bank account. In 2019, I got married and Home Affairs erroneously registered the union as In Community of Property, as opposed to Out. So her name got added to the bond. There was no cost involved, seemingly. I got divorced in 2023 and this month, I approached Nedbank to put an application in to release my former spouse from mortgage bond. Nedbank Home Loans have come back to me saying this will cost between R60 000 to R100 000. Why? I am not clear on that and the explanation I have received makes no sense to me. Because my ex-wife's name only got added to the bond as there was am error on Home Affairs' part and they registered our marriage In Community of Property, when it was meant to be Out of Community of Property. Nedbank automatically added her to the bond - there was no payment cost associated with that. There was no change to where bond payments came from. We got divorced in 2023 - there was no change to where bond payments came from. Yet now removing her is going to end up costing me up to R100 000?

Essentially, they want me to pay transfer costs of up to 100K - for a bond I already have and that was initially registered in my name and I have been paying since 2017, for a house I have been living in. This makes no sense, as well as being highly ********* and dubious.