Frustrated with service relating to these vouchers

I purchased R100 voucher via vodacom app, went to habibia express BP garage johnson road athlone ( merchant no. ***), spoke to the manager Yazeed who processed the voucher on his machine but refused to honour the voucher and did not give any petrol, i have the receipt which says 'Sale Captured'. He told me the voucher does not work on their cards machines, but if it does not work then why didn't it say declined instead it says 'Sale Captured'. I am very annoyed/frustrated with the fact that he then said to go to another bp and if the voucher then its been used, i should come back to him. Is this how bp treats their loyal customers??? No willingness to help or put any effort in to try and help.

Please assist, BP is such big company to sell vouchers and not honor after the client has paid.