possibly getting sued while broke

location: midwest united states (currently iowa)

so when i lived in missouri, i got a phone with us cellular. i didn’t know i was under a contract or anything – i was told with their new customer deal id only be paying the service itself. i was freshly 18 and on my own, thinking yeah hey, i get a nice phone they said the phone itself was free, and id only pay for service, thats cool. so i went with it. fast forward to a few months ago, i lost my job and became homeless. i have nothing. no money, my bank account is in the negatives, no food, i starve most of the day, i eat maybe once a day off money my fiancée gets from donating plasma. however, eating is already difficult because i have celiac disease – so food for me is pretty expensive. there have been times where i go days at a time without eating bc we simply can’t afford my food. well, since i couldn’t pay my phone bill, my service got shut off. they even like cancelled my us cellular account. the weird thing is, it said my balance was about $300, but suddenly now it has shot up to $500 and im not sure why. they’re threatening to send me to a collection agency who’s ultimately going to sue me because again, i don’t have a job, i’ve been trying, trust me i have, just nowhere is accepting me and i don’t understand why. i don’t own any property, even my car is in my moms name. i’m terrified of going to court. i don’t know what to do. i don’t have family to help me out, im completely alone in this. any advice would be greatly appreciated.