authorising / deauthorising a computer does not work

Hi,

I bought a new Mac and wanted to authorise that new computer. It failed by saying that there were too many devices authorised. That was true. I logged into my account and removed three old devices from the authorised devices list, ending up in a list of three devices which still should be authorised.

That's now two days ago. Any attempt to authorise the new computer ends up in an error message, that there would be already 5 computers authorised.

Seems that I am in a deadlock. I hope anyone can help me with this.