So today, I too was bit by the inability to redeem $25 Ultimate Game Cards. I picked up 4 of them, and can't do a thing with them. I can't even redeem them for $20 and again for $5... This is very frustrating...
I've submitted a billing ticket, but with an estimated 3-4 business day response time, am I still going to get the promotional bonus Zen ?
On another side note, I live in California. I went to every authorized reseller I could find of these cards in about a 25 mile radius, and did not find a single $50 card for sale... It was also quite frustrating to not be able to take advantage of the extra bonus for $50 cards.
Was you able to remedy the situation with the $25 cards? I have a single $25 card too and no idea how to redeem it as well. I emailed them but no idea what they'll say or when.