I opened a ticket three days ago with no response
It really depends on many aspects.
They could be swamped for a bit (I get the impression that this tends to happen during discount periods), it could depend on where you end up in (IIRC they have both a European and American branch, not sure about support itself though) and of course someone may have overlooked something.
Personally my treshold is usually a week or so.
@LargeBeatz My colleagues got back to you last Thursday.