The security department of my credit card company has called me twice after buying games from GOG to confirm that I really made a purchase. I mentioned to them the last time that they'd called me before about that and they said that the reason was because the purchases were made through Cyprus and apparently there are a lot of scams and fraud that funnel through Cyprus so they're overly sensitive to all financial transactions going through there.
Told them I'm glad to see they take security highly like that, but that GOG is all good. Made quite a few purchases since then and have never had them call back.
During the holiday season sales last December, I had an order get messed up. It turned out that I bought 57 games all at once and their shopping cart system couldn't cope with more than 50 so it broke and my order wasn't properly filled. I simply contacted GOG support and in less than 24 hours they let me know what the problem was, fixed it, and they gifted me all of the missing games from my order without charging me for them.
Due to the nature of the Internet and of computer software in general, it is always possible for software to have glitches or aspects of the tech to fail, especially under load conditions. My recommendation for anyone having trouble ordering from GOG is just to contact their support, they respond very quickly, soon as the office opens in the morning usually and they are very responsive and get things sorted out quickly. My experience with them is that they go beyond the call of duty to make the customer happy so give them a shot if you have a prob and they wont let you down. :)
Take care.