How to resolve an eternal loop of having paid for an update and being sent back to payment page?

After having ued a paid version 6 for several years, I thought it was necessary to upgrade to version 7 because gmail emails wouldn’t come in. 
So, I searched and found an old email from eMclient, went to their site and PAID for an upgrade to version 7.
Got an email with the activation key
Then d/l version 7, had it installed…

Next step was not so easy, I thought to activate it, but it sends me to an eternal loop, saying I have only a license for version 6 and MUST buy the new version, which I just bought.

It is suggested to ask for a lost key… then get an email (which I need to retrieve online because eMclient is no longer working) sending me the OLD activation keys.

Still nothing.

How do I proceed now with version 7 being installed? 
I tried d/l version 6 again but it won’t install as version 7 is present.

HOW CAN I SOLVE THIS? It is Saturday so I think my ticket won’t be answerd until Monday and I want the eMclient to function ASAP!