Misleading business practices

We've been using teamviewer 12 since it was launched, and we own this version.

Upon version 13's release we were found that we were unable to assist clients anymore, since version 12 apparently cannot connect to version 13. Then upon suggestion of a representative of teamviewer we did a trial of version 13.

When the trial expired, we decided we only want to use version 12, and then we found that there is no way that we can revert to version 12 (WHICH WE BOUGHT!)

Upon speaking to another representative, i was told that there is no way we can use the product that we bought. This is apparently in the "terms and conditions". Many people would consider this theft...

I then proceeded to request a supervisor's intervention, when i was told "That's not going to happen".

This is very unprofessional, and to be blunt... its theft.