I keep getting emails that there's activity in my "Tolls by mail" account, but I can't ever actually figure out what I owe

I received a toll in the mail a few months ago and promptly paid, but we've since moved and are having issues with our mail-forwarding. So I think that may be the issue.

However, when I try to search what my bill is on the website, I either have to enter the bill number, which I don't have, or I have to search by "date of travel". Considering I commute in and out of the city pretty frequently, there's any number of days this is for. So other than sitting there for an hour and searching for every day in the last month, I don't know what else to do.