It may take them a few days to get back to you. I’ve had some problems with tasks lately, that support is aware of, but no missing tasks that I’m aware of, or hmmm … maybe that is why I seem to have more free time lately.
As a thought, unless you created new notes for your tasks they should be in a note titled Things to do. If you are on a payment plan you will have access to note history. Maybe you will have a backup of that note with all of your tasks there. That said, I just checked on my system and that note hasn’t been backed up in a month, though it gets updated daily, so this special note may be excluded, for some reason, from their typical backup.