Hello There,
I'm Bambi and I'll be happy to help you with your enquiry.
If I understand correctly, you shared your subscription but the users you shared with cannot access the benefits of Microsoft 365.
The thread is a lot so I hope I got the issue raised?
To the solution, I will suggest something I have suggested to other users and have worked.
Kindly remove the users and send them a new invite via link ( I believe you mentioned you are unable to add them via email). After you have done this, find out if they have accepted the invite.
Here is how to do this: Select the Copy button to send the link via email, text, or other message to the person you want to share with. When they click the link and sign in with their Microsoft account, they'll be added to your subscription.
If they have, they should confirm it appears in their account by signing in to the Microsoft account here https://account.microsoft.com/services?ref=officesupport
If prompted, choose Sign in and enter the Microsoft account email and password associated with your Microsoft 365 subscription (the one they used to sign in earlier when you provided the link)
Review the details under the Services & Subscriptions heading.
If they find the subscription under the above they can move to the next steps.
If they have had Microsoft 365 subscriptions previously, they will need to sign out and sign back in to activate with the new subscription.
Kindly use the links below to do this:
To sign out of Office: https://support.microsoft.com/en-us/office/5a20dc11-47e9-4b6f-945d-478cb6d92071
To sign back in: https://support.microsoft.com/en-us/office/b9582171-fd1f-4284-9846-bdd72bb28426
I hope this information helps. If you have any questions, please let me know and I'll be happy to assist you further.
Regards
Bambi