Recourse after a denied Condo Insurance policy claim - help

[Irma Vazquez]

I recently had exterior and interior damage to my IL 3 unit condo property and personal unit within it resulting from a neighbors's clogged, flooded gutter and the excessive Chgo spring rains.  I had 4 policies on the property (1 for each unit plus building condo policy) at the time of event.  I opened a claim under the condo policy and after several months, it just came back denied. I'm shocked!  

Of the next steps to take to pursue coverage, I'm not sure what would be the most advised or in what order so looking for pros/cons from those experienced and/or referrals for these or other options:

- hire a public adjuster

- follow insurance appeal process

- open a new claim under homeowners policy

- consider litigation against my insurance company

- change insurance companies (I'm seriously wanting to do this with a company who can insure my unique mixed use space)

Your thoughts and any referrals of resources is appreciated too!

Thanks!