Yeaaaaaah . . .
I think it’s fairly common for hospitals to create a new account for each visit. My wife was in the hospital 4 times between October 2017 and February 2018, three times inpatient and once outpatient, and the second time was actually at two different hospitals, so we had to deal with all of that. I had to negotiate a payment plan on each bill separately (or at least those not paid by the insurance). It was particularly bad because of the timing: the first two visits were on one plan year and the second on another, so the deductibles reset.
I did have two bills end up in collection. In both cases, though, the collection agencies were fairly easy to deal with. I contacted them immediately and told them what I thought I could afford, and they largely agreed with it. In one case, I had a plan through the hospital but was late on one payment, and they shot it straight over to collection, which really irritated me.
Anyway, I feel for you. A lot of people end up in the same boat these days. Even doctors acknowledge that the health care system is broken. Fixing it without breaking other things, though, is not at all easy.