My BtYahoo email firstname.lastname@example.org has been suspended due to suspicious activity. Can someone help me retrieve it?
can you access you email using web mail and not an app
Can you try signing into your email using the link https://www.bt.com/btmail
As this is a talk21.com legacy email address the security information BT hold for you may be severely out of date. The best process is to go to the BT Email login page at https://www.bt.com/email and click on the "Forgotten Login Details" link underneath the password box.
This will run through 3 or 4 steps and will ask you to confirm your email security information. If you cannot get past this stage then give the email team a call on 0808 100 6778 so they can look into it for you
Won't log into account by webmail or mobile app
Its likely to have the "Potentially Compromised" flag on the account preventing access. Resetting the account password will remove that flag and resecure the account
Can you click on the "forgotten password" when logging in on that link? This should allow you to reset the password as @WeekendTechie has said, which should recover that account.
If that doesn't work, please post back to me.