Charged A No-show Fee For An Appointment I Canceled, And They Billed My Card Anyway

location: Colorado, USA. I had a new patient appointment scheduled with a dental office in mid-December 2025 (basic exam + x-rays). The day before, they texted me a “confirm” link. I clicked confirm, then later that same day my work meeting got moved and I couldn’t make it. I called within an hour and got their voicemail. I left a message saying I needed to cancel and asked them to call me back. Nobody did. The next morning (day of the appointment) I called again as soon as they opened and spoke to the front desk. I said I needed to cancel and asked if there was any fee. The person said “okay, I’ll take you off,” and that was it. I also want to mention I had paid a small booking deposit ($25) when I scheduled online, and they kept my card on file for that. About two weeks later I got an invoice for $175 labeled “missed appointment fee / service.” I called and they told me I was a no show and their policy requires 24 hours notice. I explained I left a voicemail the day before and also called again the morning of, so I did try to cancel. They said voicemail “doesn’t count” unless a staff member confirms it, and canceling the morning of still counts as a no show. I asked for a copy of the policy I supposedly agreed to. They emailed me a generic PDF that looks like a form, but it doesn’t have my signature or even my name on it. Then yesterday they charged my card for the $175 anyway. I did not authorize this charge , and I never received any service. When I called about the charge they said it’s in their “financial policy” and they won’t refund it, they just repeated that I “accepted” the policy by booking.

Legally, can a business in Colorado charge a card on file for a disputed no-show fee without getting my explicit approval at the time of the charge? Does leaving a voicemail cancellation matter at all, or can they say it’s invalid unless they confirm it back to me? What’s the best next step: dispute with my credit card, send a written demand for a refund, file a complaint with a state agency, or something else?