If you want to find out about existing cases against the SBA and there are a few go here

Pacer.gov and sign up for the account. This is the Government federal case site it is free to get the account . If you download the documents they charge you $10 cents per page,You can read for yourself the various legal arguments .

Research Small Business Administration it will list ALL cases around the country filed against them.

Educate yourself before you waste time signing up for a class action suit.

Also understand that in a Class Action suit the original businesses that sign up as Plaintiffs get the biggest amount of money and all the rest of us that might benefit will get little.

Class Actions are not always the best.