Open Question: Can you be sued over $153 in medical bills?

I have paid off a $150 medical bill and have been trying to make arrangements to pay another $153 medical bill. I have had a couple of life changes. I am now sober but find myself caring for my parents. I also have a disability claim out there because I am chronically ill. Now, I get a threatening letter in the mail after they have not worked with me (not the other way around!). I can take