Twenty-seven million Americans were contacted by a collection agency about unpaid medical bills last year.

A new Federal Communications Commission ruling makes it more difficult to track down those debtors on their cell phones, according to the collection industry. 

The new rule clarifies that collection agencies can “robo-call” someone on a cell, but only if that person consented to those calls for billing issues.

Robert Foehl with the Association of Credit and Collection Professionals says the problem is when a person changes numbers.

“You are still on the hook from a liability perspective if you make a call to a new person who owns that phone,” he says. That means companies could face fines of up to $1,500 per call. 

Medical debt is big business in the U.S. 

According to NerdWallet, Americans paid three times more for medical debt than bank and credit-card debt combined in 2012, collecting $21 billion from consumers.

Margot Saunders, an attorney with the National Consumer Law Center, says the FCC ruling may prompt the industry to curb its practices.

“This is a situation where debt collectors are calling the wrong people far too many times,” she says.

Saunders says companies will only pay fines if consumers feel harassed and file a complaint. She says industry has other options including email, “non-robo calls” and snail mail.

The industry argues that adds expenses that will be passed on.