I need some legal advice?

Been getting a lot phone calls and now a letter in the mail from Law Offices of Joel Cardis LLC, http://www.joelcardisllc.com/ say that we own over $400 to a day care my kids went to 2 years ago! Thay have my wifes name with my SSN. I pretty sure we dont own them any money and if we do why are we hearing about this now after 2 years!? I never heard of this "law firm" before. I Google there name and phone # and found a lot of complaints about them haring people over the phone. Wondering what should I do now? Since it is with this law firm now I really can't cotact the day care about it now right?