VanGe1: I had a similar problem about buying GOG games with a Paysafecard from Cyprus, but the problem was never solved. Instead, GOG stopped accepting Paysafecards from Cyprus. So I didn't have the chance of buying anything on GOG. Now I'm hoping that the upcoming GOG "wallet" will solve the problem.
Well, you can't really blame GOG for most payment related problems. Mostly it's problem with country payment is made from, bank or card being used or GOG's payment processor (based in England). Site side failures are far rarer and mostly happen during big sales when servers are overburdened.
In Cyprys Paysafecards case it's probably related to Cyprus' reputation of being major source of credit card fraud thus many banks block transactions to and from there. GOG itself had lot of problems with that in it's early years as it's incorporated in Cyprus. Still happens from time to time even today.