I did try PayPower for a while. I thought it might be attractive because I could find reload cards that could be loaded for up to $950. So this would have basically halved my cost in buying reloads.
I was able to make the initial purchase of the PayPower card with a credit card, and I think I bought my first reload pack with a credit card. But I very quickly ran into the same problem as you - the local stores that sell reload cards (which were supermarkets) wanted cash to buy the reloads. It was just too much hassle to try to find cashiers who would let me pay with a credit card. So I abandoned this experiment. I called to cancel my account. It took a few weeks and then I received a check for the account balance.
On to greener pastures....