FRANKFORT, Ky. -- When Kentucky passed a law in 2010 to require insurers to cover autism treatment, Heather Dales felt as if a weight had lifted from her family.

Until she billed the insurance company.

Since the law took effect in early 2011, Dales said the plan failed to reimburse her and her husband for tens of thousands of dollars' worth of care. Most of it paid tuition to the Highlands Center for Autism in Prestonsburg, Ky., which she said drastically improved the development of her son, Hunter, now 6.

Dales said the insurer has denied most of the claims, citing incorrect billing codes or use of an unqualified therapist -- among other reasons. The couple first turned to family fundraisers -- and now loans.

In the past few years, more than half the states have passed legislation mandating some level of autism coverage, according to the National Conference of State Legislatures. But some families of autistic children say they've received little or no benefits.

Insurance companies in Kentucky say the state's mandate has required a smoothing-out period to address legal gray areas and other unforeseen challenges. Autism advocates say insurers have had plenty of time to cover everyone who's eligible.

"I don't see any basis for why this should be happening two years down the road," said Daniel Unumb, executive director of the advocacy group Autism Speaks. "I think they're still looking for a way to avoid the broad policy and the mandate."

Last month, California issued emergency regulations have plans to comply with the law after the state received 71 complaints. Missouri's Department of Insurance took action in September against insurer Aetna for excluding autism coverage, which resulted in the company donating $250,000 to a not-for-profit treatment center.

Kentucky's Department of Insurance also has been involved. After receiving complaints, the department issued an advisory opinion in May to clear up confusion regarding which kind of providers are covered under the mandate. But nearly a year later, some parents say they're still waiting for reimbursements.

Professionals identify one in 88 children as having Autism Spectrum Disorders, which can cause social and behavioral challenges. It's often treated through applied behavior analysis, known as ABA, an intensive one-on-one therapy that focuses on specific goals, such as toilet training.

Shelli Deskins, director of the Highlands Center, said Anthem Blue Cross Blue Shield of Kentucky has failed to reimburse six Highlands families, including the Daleses. The parents of one Highlands child, Mitchell and Debbie Crum, have sued Anthem in federal court over alleged failure to reimburse. The case is pending.

The center charges $60,000 a year in tuition, although scholarships may offset a large percentage of the cost. Kentucky's law requires large group insurers to cover up to $50,000 a year in autism services for children between the ages of 1 and 6 and $12,000 a year for children between ages 7 and 21. Small group plans must cover up to $12,000 a year.

Deskins said the center is making progress with Anthem. In January, the company agreed to pre-certify some students for treatment at the school, although reimbursements are yet to follow, she said.

"Families are still not getting paid what they are entitled to by the mandate," Deskins said.

Tony Felts, an Anthem spokesman, declined to speak about the claims of specific families. He said Anthem is "making progress" with Highlands.

Felts said Anthem has overcome several unforeseen obstacles to provide coverage. One was the initial confusion about which providers are covered. He said Anthem reprocessed the claims it denied over that issue following the Insurance Department's opinion last year.

Felts said Anthem has paid out $350,000 in autism-related claims since 2011.

"We want to do this right," Felts said. "We've spent hundreds of hours to comply with this mandate, but it's a huge job. There's been a learning curve. And I think there's been a learning curve for both the insurer and the payer community as well as for the provider community."

Melodie Shrader, executive director of the Kentucky Association of Health Plans, said insurers and providers still were meeting several months ago to work out their respective confusion.

"We went through those bumps in the road," she said. "And in the last six or eight months we haven't had those meetings ... because things have worked themselves out."

Not yet, according to Deskins and some parents whose children attend the Highlands Center.

Tyler Hall said he moved his family from Lexington to Prestonsburg so his son Jacob, now 4, could attend Highlands. His daughter Maggie, 23 months, also receives therapy there.

Hall said that he and his wife also have paid tens of thousands of dollars toward their children's care. He said their claims have been denied except for some speech therapy lessons.

"It's been a nightmare from the get-go," he said.