That's a shock! Good to know: we never remove lessons without mentioning it to you.
The cause is often simpler. You probably have two or more accounts in LessonUp, and you are logged in to an old or rarely used account.
To check/confirm this, try logging in with a different email address. If this does not work, you can contact us via the chat.
Do you have multiple accounts and would you like to delete or merge them? Then please contact us.