US medical-bill rights check, quiz-first (no documents): No Surprises Act protection (45 CFR 149 incl. the never-waivable §149.420(b) list), good-faith-estimate disputes ($400/120-day rules), nonprofit-hospital financial assistance + collection shields (26 CFR 1.501(r), 2026 FPL math), ACA appeal deadlines (180-day/4-month windows computed), Medicare MSN redetermination. Citations + deadline math, honest no's. No LLM.