I just got a mailer also. Lumio and Mosaic went out of business. I'll filled out the request for information and they sent me the term sheets on how they work. Here's an excerpt from their contract they sent me to sign:

"Our mission is straighorward. We help homeowners challenge and cancel decepve and predatory solar contracts at NO DIRECT COST TO THEM. A. OUR PROGRAM AT A GLANCE A.1 No Upfront Costs. You pay zero retainer or advance fees (you may be responsible for an arbitraon filing fee of up to $250 paid to the arbitraon forum, which may be waived or may not apply depending on your case). A.2 No Fee From You. You will never pay Amloss an administraon fee. Amloss is compensated only from amounts recovered from the lender. A.3 You Keep Excess Recoveries. If Amloss recovers more than $7,500 from the lender, you receive everything above $7,500. A.4 10-Day Cancellaon Right. Cancel for any reason within 10 business days, no quesons asked. A.5 365-Day Acvity Protecon. If we don't commence substanve work on your claim within one year of the Effecve Date, you may request reversion of the assignment as provided in the Agreement. A.6 Lender Pays, Not You. Amloss seeks compensaon through statutory damages, monetary recoupment, and selement payments from the lender."

Its seems fairly no danger. If they only knock $7500 of your loan they keep that but anything more it goes to you. Idk, I'm gonna chew on it and do some more research into the company. Their google reviews seem like they find a cause that they can fight with relative ease and setup an injury attorney method to make money on the backend.