PNP Blackheath

On the 6th of July I went to PNP Blackheath to buy electricity. I had two gift cards for 100 and 250, so I bought 350 electricity, and then the transaction declined the use of 2 cards for the same product. The transaction was cancelled, the 100 card remained but the 250 card was zero balance. They said it will return within 24hours. I have been visiting the shop twice a week and to this day the 250 vanished into thin air. 🤦 No one to update me.