Is it that the insurance won't cover the intensive outpatient therapy at all, or just the program you've been accepted to? It could be that the two other programs you received denials from are the ones in your insurance network and the other one is not. Often what you can do is call the insurance company and tell them that you tried to go to one in network, but they were not able to take you. Then they can sometimes make provisions for you to use one out of network as long as you have the documentation that you tried to stay in network. It may come with a higher coinsurance or some other adjustment, but you could still go.

If it's a matter of them not approving the IOP at all, then your doctor can appeal to them saying you need this level of care to avoid going into an inpatient situation, which would undoubtedly be more cost-effective for them. (You've got to speak their language, and money is one thing they definitely understand.)

I hope you are able to get the treatment you need soon.