Hello,Rene Weinrich
Welcome to the Microsoft community!
I have realized your issues.
Before that, I would like to ask you for some information to better address your question.
Where did you purchase your original subscription? Did you have a key before?
Nowadays office products use digital licenses, digital licenses are tied directly to the account, there are no physical keys.
Also Microsoft 365 subscriptions are not transferable for account use.

Transfer Microsoft 365 Family or Personal to a different Microsoft account - Microsoft Support
You can sign in to https://account.microsoft.com/services to check you current subscription
Feel free to post back if you need further assistance.
Thank you for your understanding and patience and I look forward to hearing from you.
Ryan - MSFT | Microsoft Community Support Specialist