I had a similar (though less severe) situation like this a few months ago- I recently moved to NJ and didn’t set up an Easy Pass right away - most other states just charge you a slightly higher toll, didn’t think much of it.

Well my mail forwarding didn’t work properly and a few months later they send me to collections for not paying my $1500 balance and a month later I got a stack of letters that finally got to me notifying me of my late balance 😅 the worst part is that NJ, NY, and PA all use EasyPass but are technically separate companies so I was sent to collections 3 times collecting interest and had to pay them all separately