Same here. There was a post I read where an Avast mod said that the email could be in spam and deleted forever. They couldn't really do anything and had to do a reset on their server side, thus causing all the synced data to be lost.
For my case, I probably activated Passwords few years ago using a device which I am no longer using. I too don't remember receiving any email about restoring. I am willing to start anew though, so if any Avast mod could help me to reset/remove all authorised devices, please do! Thank you!