Can't buy gems
Your best bet is to contact the CS Team via the ‘Support’ link above/below and ‘Submit a Ticket’ while waiting.
Good luck.
FWIW, I had problems purchasing gems via credit card. I googled and found the most amazingly stupid sounding suggestion for fixing it….
when you put in your card details (like, name on it, etc), use ONLY LOWER CASE LETTERS.
I tried that, and it worked. I then sat there for five minutes and wondered how amazingly bad something at Digital River — who do the credit card processing — was broken that it couldn’t cope if I used uppercase.
Anyway, try that: put in all the details for the card and everything in lower case. If it works … laugh bitterly about how bad programmers are, I guess?
(Note: that’s definitely not an arenanet issue, but Digital River, so I didn’t bother to ticket it to anet. You can if you want, though. They might yell at DR for being dumb.)