Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Dear Jessica,
I am sorry this is holding up your work, that is understandably frustrating when you cannot use the apps at all. Unfortunately, this is a public community forum, so no one here can access your account, activate Office, or arrange a callback. And as a forum moderator, I am not able to review your subscription or license assignment to diagnose and fix this directly. My role here is limited to general guidance you can apply from your side.
That said, the behaviour you describe is common after moving from personal to business. The desktop apps stay signed in with the old personal account, so they do not pick up the new licence automatically. In any Office app, go to File > Account, select Sign out under User Information, then close all Office apps and sign back in with your new business account. It is also worth confirming in the Microsoft 365 admin center that a licence has actually been assigned to that user, since a subscription can be purchased without the licence being assigned.
If that does not resolve it, you can request a callback. Sign in to the Microsoft 365 Admin Center using your business administrator account, which may end in .onmicrosoft.com and open a service request through Help & support, which lets you request a call rather than wait on hold. Details on that process are here: Get support - Microsoft 365 admin.
Hopefully the sign out and sign in clears it straight away. If anything is still not activating afterwards, feel free to reply here and I will help you narrow it down.