FNB Enhanced Due Diligence Form and overall bad customer support

Been banking with FNB for over 10 years.

Now they're undertaking a KYC process whereby they're asking me to fill in a .pdf form whereby one of the fields (tax number) is uneditable.

I've sent my tax number to them, however they insist this uneditable field needs to be filled in.

Been going on for over a month now, and they're now threatened to suspend my bank account.

Poor customer service.