How to deactivate an activation code?

After having an error (HTTPS error 501: Protocol “https” not supported) while trying to deactivate an old version of paquet builder, I’m now unable neither to activate my new version (3.7.1) nor to deactivate my old version. So I’m stuck with no available commercial version.

I already sent 2 messages to the support team, even try to phone them (not responding), but I get no single answer so far. So my question is : how can I deactivate my activation code when I have no more active installation ? Thanks in advance