I'm puzzled regarding GOG Support's reaction - if no-one got into the OP's account, why did he receive a GOG email that his account email had been changed to a Russian one? And from what the OP says, it was indeed the case.
If the OP pre-ordered
TW3, in which case he got a gift code for
Neverwinter Nights which he apparently hadn't redeemed. It's possible that whoever hacked his account, was interested in the game and redeemed it.
And if the addition of that three-digits number to their username happened this recently, it's really sad that this bug hasn't been squashed after all this time.
PaterAlf: While there has been several topics lately, the impression that their customer support is terrible at the moment might be wrong.
Most of the time people only write about their experience with customer support when something went wrong. Nobody bothers to create a topic when everything worked smooth and without any problems.
I had to contact them several times over the last few years and for me support was always helpful, competent and reacted very quickly. I might just have been lucky, but it could also be possible that 90% of the customers share my positive experience and the people that complain are just a vocal minority.
While it's generally true that people very seldom post about their positive experiences, you have to admit that the frequency and number this sort of topics has increased, which is a likely indication of a decline in the service, and should be taken into account by GOG itself.
Good to hear that your experience with GOG Support has been nth but positive, especially if your latest one was recently. Was it?