Teamcity professional can't use build agents

We run a Teamcity Professional Server on premise. That comes with three licenses for build agents.  Now we bought 23 more Licenses for Build agents. In former times a Build agents could be activated by adding the Build agents License Key to the Teamcity Server. Now with the new Licensing Model, the Build Agent License must be in the same team as the Teamcity server, but it is not possible to transfer a Teamcity professional Server license to the other Team (with the licenses of the build agents) and it is not possible to transfer the Build Agent license to the team for the teamcity professional license. The only option one gets, is the creation of a new team. Since you can't “buy” a Teamcity Professional License it is not possible to add a teamcity professional license to the Team with the build agents. Also, there is no option in teamcity to go back to the single key activation system. We are stuck with 23 build agent licenses that we can't use and a teamcity server with a build queue of several days now. And jetbrains support seems to ignore us completly