Nedbank Cardless

I have money that was sent to me via a Nedbank Voucher their ATM keeps on saying voucher is used whilst I never got that money. Last week Friday I went to the Kempton park Branch and their service champion told me it's very difficult to withdraw with a voucher I must tell the person who sent me money to phone Nedbank and request a reversal..I Must really ****ed with their service because how can they have an option and it's not working? Now their employees also don't seem to understand that option..can someone from Nedbank explain as to how am I going to withdraw that money because I need it it's mine why must they keep sending me from Pillar to post