Erie auto insurance issue- was I even insured?

So I set up your insurance for two of my cars about three months ago. I contacted a local rep that had set everything up for me and sent over my ID cards. I gave her all the information for automatic ACH payments, and all of my automatic payments come from a very specific account that I don’t really check often. I just received a letter three months into my plan, that stated that I was automatically being canceled because my signature page wasn’t returned. When I reached out to my rep and asked them what was going on they said that I must’ve missed some thing in my email and that’s why they were canceling. I basically just sardonically replied “great,thanks” and was on my way to finding a new insurance provider.
This was a week ago, and I hadn’t heard from her again. I then received a bill Thursday, explaining that I owed over $1800 and that my
bill has not been paid since the plan had started, and that I was responsible for the the entire cost of the plan. I messaged my insurance agent again saying what’s this, and received no reply – so I contacted corporate said that she had dropped the ball by not making sure all my documents were signed or submitted. I’ve checked my emails 1000 times I never received anything that I didn’t sign and return. The corporate agent also adamantly explained that I was absolutely insured for those three months that I am on the hook for now that weren’t paid because my signature page wasn’t signed. My issue, is that because I don’t have that these forms to go over I don’t know if I was even insured or not and I’ll never know because I had no reason make a claim.

The local agent had said she processed my first payment, and everything was good to go, but from what the rep said the signature page is what would have started the payments?! i have no idea what the signature page actually enacted or not, and I’m concerned I was never insured whatsoever because it wasn’t signed. Anyone familiar with what this signature page would have been for?