Nedbank and Ver-tex solutions lack of communication has me paying on an already settled account

I recently settled my personal loan with Nedbank Nedbank gave me a settlement letter but the agent whom i dealt with, failed to notify me that the account was with thier legal firm, Ver-tex solutions.

The lack of communication between Nedbank and Vertex, to inform them that the had been settled,meant that Ver-tex debited from my account as per usual. i have been in trying to get in contact with Vertex so that they can credit back the amount into my account, with no luck, as the number prided on their site states that it is out of service.

i have logged a query on Ver-tex'site to dispute the debit but have received no feedback. i have sent them numerous mails on the matter and they dont respond to my mails.

i have been touch with Nedbank to intervene on the matter but they have referred back to Vertex, even after stating that my calls through to Ver-tex solutions aren't going through