As of Jan. 1, a new law is supposed to prevent most surprise medical bills, but there are some loopholes to be aware of.

“My health was deteriorating and I had to have a C-section immediately,” says Kelly Kantor.

When Kantor gave birth to her son, Hudson, he had to spend two weeks in the neonatal intensive care unit, but then the medical bills came. Even though her hospital was in network, the NICU doctors were not – she was told she owed nearly $20,000.

“You wouldn't think – Oh wait! Don't touch my son! Are you in network?” says Kantor.

Lisa Waterman was hit with surprise medical bills twice. First, when her son, Dylan, was born, then when her other, son, Brandon, was bitten by a dog, and the in-network ER called in an out-of-network plastic surgeon.

“We spent about a year going back and forth with the plastic surgeon's office, but we still paid almost $4,000,” says Waterman

Studies have shown six in 10 Americans have been hit with at least one surprise medical bill, but those nasty surprises should be less common now that Congress has passed the No Surprises Act.

“You could go and have a surgery, and the surgeon was covered under your plan, but the anesthesiologist was not, and so those are the main situations that we were trying to avoid,” says Rep. Frank Pallone.

The act says you can't get a surprise bill for most emergency services, even if they're out of network. You can't be billed more for out of network emergency care than in network, and if you pay cash, you have to be given a good faith estimate. But Kane In Your Corner found there are loopholes in the law.

Greg and Sugar Bull, of California, had twins through a surrogate, then were hit with surprise bills topping $80,000. Both babies spent a week in the neonatal ICU, but the insurance company claimed it was not emergency care. They eventually resolved the case, but health care advocates say what happened to them can still happen to you.

Ann Marie McIlwain says there are other red flags to watch for, such as ambulance service. Air ambulances are covered by the act, but ground ambulances sometimes are not.

“When you are transferred, let's say from the hospital to a skilled nursing facility, or taken from home to a hospital, that is not covered in this bill,” says McIlwain. “Unless it's life threatening, do not get in an ambulance, if you can help it.”

There's one other thing to watch out for: the calendar. If you get a medical bill that violates the act, you have 120 days to appeal.