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Dear Money Helps: I have sleep apnea and signed up for a study at the Stanford Hospital Sleep Disorders Clinic. I paid a $15 fee, answered questions and was checked out by the staff. The whole process took 30 minutes.

I was told I couldn’t proceed to the next phase until my health insurance was verified. My insurer told me later that week I wasn’t covered. Much to my surprise, I got a bill for $420 for the consultation. I called the customer complaint number on the bill but was told that the charges were final. I paid the $420 but feel like I was ripped off. – Christopher Camba, Hayward, Ca.

Answer: You’re not the only person to lose sleep over a medical billing snafu. According to medical bill auditor AMBR, 85% of hospital bills contain errors.

Yours was one of them. When the manager of the clinic reviewed your record at our request, he found that you were charged a co-pay for the consultation, as they assumed your insurance would cover the rest. (Yes, that 30-minute appointment goes for $420; the study itself would’ve cost thousands.)

He admitted it was their failing - that they should’ve checked with your carrier before naming the price - and agreed to refund your $420.

You did the right thing trying to dispute the charge, but you didn’t go far enough. The clinic doesn’t have any written record of your inquiry. Consumers have to be vigilant when it comes to unraveling billing mistakes, says Nora Johnson, associate director of Medical Billing Advocates, a trade group that trains people who represent patients in disputes. Should you notice something amiss in an invoice, she says, don’t pay it.

Instead, initiate a dispute by phoning the billing office, making sure to write down the time, date, name of person you speak with. Follow up with a letter, sent via certified mail, to the highest person in the department. (Once they have a written complaint, most providers halt the collections process until the case is closed.)

If you still get the runaround on a sizable bill, consider hiring an advocate. You’ll be charged, hourly or by a percentage of what’s recovered, but at least you’ll rest easier knowing you have a professional red-tape cutter on your side.

Next time, talk to your insurer before going for any procedure or service. If you know what’s covered, you’ll be less likely to end up in a billing nightmare.

TIP: If you want to dispute a charge, act fast. Medical providers are
aggresssive about unpaid bills and many will send delinquent accounts to collections in less than 90 days.