I paid for a yearly subscription and it won’t let me use the site due to trial expired.
On the “support” section of the main website (found in the menu on the top right), there is a contact form for account and billing related issues. Use that and someone will get back to you within 24 hours.
https://www.askmrrobot.com/support
(Sometimes this happens if a person is not logged in with the same username they purchased the account on - so you could also check that too, but if that’s not it, we’ll have to look up your account and figure out what happened.)