First, if you have a Groove Agent 1 disc - no matter if second hand or not - you can use it to request an update for Groove Agent 4.
Groove Agent 1 does not have to be installed on the new system to run Groove Agent 4.
And yes, we have been busy or better not well staffed over the last week… sorry for that! Most of the team is back though and you should receive answers - at least if you have requested support from the European support team.