Hospital bill sent to collections after itemization/consolidation

Hello and thank you in advance for any responses. I’m looking for guidance on what to expect from a conversation had with hospital billing regarding a bill we received from collections.

My wife had our second child a year ago and we’ve been paying our portion (after insurance) ever since.

We had requested an itemized bill after receiving countless separate bills and the hospital ended up consolidating what we owe into one single bill (or so we thought).

A collections notice for $1300.00 was sent to us, stating the original balance of $4000.00 was sent to them from the hospital we’ve been making payments to.

A representative for the billing department thought we were calling to have them take the debt back and immediately informed us that it wasn’t possible.

After going around and around they finally stated they see in the system that it was sent to collections earlier in September. The tone started to shift and eventually they said it was an error for that bill to not have been apart of the total amount originally consolidated.

We’re waiting to be contacted by a “supervisor”.

We call every month to confirm payment and were never made known about this bill.

Is it wrong of me to think this bill from what seems to be out of thin air, is not our responsibility? I am not on hospital payroll and don’t get paid to find their oopsies. Especially when the only one negatively affected is us.

Edit: This is in Florida.