Last time I had a issue with Microsoft Office product. The product showed wrong Belongs to information. I had activated the Office product with my Office account, but still it was showing product belongs to xx.
I was able to fix this issue with the steps below.
Step 1 : Go to https://portal.office.com/Account/#homeand sign in using your work or school account, if prompted.
Step 2 : From the Install status tile, select Manage installs.
Step 3 : Under Install status, select Deactivate to deactivate the Office installs you no longer use.
Step 4 : Now we need to start CMD as Administrator.
Step 5 : cd c:\program files (x86)\microsoft office\office16
cscript ospp.vbs /dstatus
Note: If you are using Office 2013, replace Ofifce 16 with Office 15
You will get this result, now copy the product key what you want to delete.
Step 6 : cscript ospp.vbs /unpkey: HT7KC
Step 7 : Go to control panel\user accounts\credential manager and remove microsoftrelated credentials.
Step 8 : Reboot the computer and start (for example) word.
Step 9 : Reactivate your office with your office 365 home account.