Hi I have a problem, is that when I go to try Harmony Premium for 21 days it tells me that I do not have a license on the account, ask the support and they told me that I should first return the license and then activate it again, but there is no license for Return, all spaces blank. what I do?

You need to contact Toon Boom Support again.

This is just a user forum.

Surely no one here would have more knowledge than Toon Boom Support regarding this matter.