Receiving a licence violation message without reason

I had some Problems with the eM Client not synchronising correctly, this we solved but now I receive the message that there is a Licence Violation Problem, even tough we did not Change anything and only 2 e-mails are connected… how can I solve this Problem?

Hello,

In this case, you were suspected of using the FREE licence for a commercial purpose which is considered as a violation of our licence policy. We informed you with an email notification but after you refused to answer, we deactivated your licence. If this is a misunderstanding, please contact me at [email protected] with an explanation.

Thank you for your understanding.
Russel