I do not want to appear impatient, but I would like to use the stamps collection offer (The gamers and Witcher2) for a birthday gift and I am still waiting the email... When does it arrive?

Normally you should have already gotten it, but it seems that some people are experiencing some delays. So first check your spam folder just to make sure it landed not there and then write to support. But be aware that the support seems to be kind of slow at the moment because of a high number of tickets :-)