Hi,
Office will not activate unless the device is signed in only with the account that owns the subscription.
What I suggest is:
Sign out everywhere and sign in only with your personal email:
Open Word → Account → Sign out
Windows Settings → Accounts → Access work or school → remove the old work account
Reopen Word → sign in with your personal email (the one you paid with)
That usually fixes activation immediately.
About talking to a Microsoft support:
Go here: https://support.microsoft.com/contactus Choose: Microsoft 365 → Billing → Subscription help → Chat/Call with a live agent
You can request a call from an actual support.
I hope this helps!