Nedbank refuses to pay back money from atm deposits with incorrect reference number

I have been fighting with nedbank since 04 December 2019. I deposited money into a atm with the incorrect reference number for my credit card. I noticed the mistake and went into the Stillbay branch where I was told the cannot help me so I called nedbank head office where I was given a email address,*** and was told to attach the slip from the atm and explain the situation. I contacted them the next day and was told they have not received proof of payment,sent it threw again. Did a follow up 2 days later where I was told that I need to go into the branch because it was a cash deposit. I am un able to visit the branch ,I have called more than 50 times,sent multiple emails but have had no response. They refuse to give my money back and because of this my credit card is now overdue which affects my credit score.