Vodapay BP voucher shambles

Sent from pillar to post by Vodapay and Payment 24 support staff; no resolution. I bought a BP voucher on the vodapay app. When trying to use this at the petrol station the transaction is 'declined'. When I queried this with vodapay support, they sent me on to Payment 24. Firstly, there was no answer. Once I managed to get through, the agent eventually confirmed the voucher had not been redeemed and I should call again when I'm at the petrol station in case it gives another error. So I did. Then the agent told me the voucher had been redeemed for a different value in a place where I have never been before. He sent me back to Vodacom support to find out what is going on. He also said the same voucher number had been issued for a different value. This is not the first time there are problems with the system. Appreciate if someone can look into this.