How to handle what could be a non issue

So i brought my 2yr old to the er while we were in GA about 3 months ago because she had a 104.8 fever. Situation was adressed and we paid a bit of money at the time services were rendered.

Here is the gig. We never received a bill for the rest of the money that was owed. The hospitalcalled twice saying they were getting the mail returned so I verified our address twice. We finally got a bill in the mail a couple days ago and paid it with a e-check.

I just got a call from a collections agent saying the doc turned me over to collections. My question is if i just pay them, will mycredit score get hit or has it already been hit by being turned over to collections? It just seems fishy that iam getting a bill fromthe er and the doc. Is that standard er practice?

This whole thing could be a non issue if i pay the debt collector but it pisses me off that through no fault of my own, im being treated like a common poor.
I am poor but i pay my debts :)