Useless Nedbank App

I bought electricity on Nedbank money App on 06/04/2019, and i still have not received my voucher. I have been at the branch on several occasions with no joy as the Simmonds street branch STAFF in JHB branch said they can't do anything to help me because it was bought "digitally" i don't even know what that means. The call centre service is terrible as i always spent no less than an hour on hold with no assistance. I would like to get my money back as i don't need that voucher anymore it's been a month already, and i don't expect any charges for reversing my money because it was your App that is not working properly.