How to deal with medical bills from a night I don’t remember too well

Last year, I had a psychiatric crisis which involved 2 ambulance rides and an inpatient stay (involuntary). For the inpatient stay, I was approved for financial assistance by the hospital due to low income and I didn’t have to pay anything (for which I am incredibly grateful!) beyond what my insurance covered.

For the first ambulance ride, I received the bill in the mail and set up a payment plan. I guess the ambulance is separate from the hospital so the financial assistance did not apply (the ambulance bill is from “City of X” whereas the inpatient stay bill is from a specific private hospital).

I assumed at the time this bill covered both ambulance rides, because I logged onto the patient portal for the city and the total amount was consistent with this bill. However, unbeknownst to me, there was a separate account number for the second ambulance ride which I never received since I moved and somehow my mail was not forwarded.

I only learned of this second bill yesterday when I was called by a collections agency which the city apparently sold the debt to. All in all it was $4500 total for the two ambulance rides (which was probably about 10 minutes total …), and my insurance paid about $1400.

Now, in addition to the impact to my credit of this particular unpaid bill (unsure yet whether they’ve reported the debt to the credit bureaus – my credit score on CreditKarma has not been impacted yet though), what worries me is that there could be even more unpaid bills out there which I missed due to my mail not forwarding (I’m looking into that as well). I honestly don’t remember that terrible night too well.

So, I have two questions:

Is it worth it to try to negotiate with my insurance, the city, or the debt collectors? Or just pay the debt collectors (if it’s verified that this bill is legitimate)? I probably wouldn’t want to do another payment plan since that’s yet another thing to remember – I didn’t really need to do the first one but figured why not since it’s interest free.

Anyone have any ideas about how to check whether I have any further medical debts from this night (ideally before they go to collections)? I plan to call the city to ask tomorrow. I doubt I would have any debt from the hospital due to the financial assistance that was already applied.