STOP phoning for staff that left years ago

We have a member of staff that has a loan with African Bank. This person unfortunately left our employ 2 years ago. I have been struggling with African Bank to stop phoning us every day to ask to speak to this person. I have logged official complaints, gone to the Banking Ombud but no such luck. Receive a phone call every day asking to speak to this person. Sending e-mails to *** makes no difference. What will it take for you to stop harassing us?