Is there a 90 day limit on storing emails?

I've had the same Cox email since around 2012, (Cox made me set up as a new customer when I moved to Nevada, even though I was with them for some 20 years in Louisiana.) Fairly recently had to do a fresh install of Win10 and after reinstalling my email program (Thunderbird) I only seem to be allowed to see my last 90 or so emails. that limit is also suddenly imposed on my iPhone and iPad. It used to be some 2500 emails. From what I can tell, any emails older than 90 days are vanishing.

According to the email data bar I'm only using fraction of the 2GB allowed. I used to be able to see emails from a few years ago, but now it's only from the last 3 months. The 'Archived' folder is empty, and I also emptied trash and junk folders.

Is there a way to access my old emails, as sometimes I need them to reference a date on a purchase, a subscription, or whatever.