The National Association of Guide Dog Users (NAGDU) has opened a hotline which offers information about the legal rights of individuals who have service/guide dogs; they also offer the option to speak with an advocate who is specially trained to resolve issues of access denial.
You can reach the holine by calling 1-866-972-3647. You can also find more information on their website: National Assoc of Guide Dog users .
More information about the hotline, and exerpts of the pertinent Federal laware available by clicking here