Veteran vs Illegal Using SSNs

Illegal use of my SSN by a company and illegal immigrants have destroyed my credit. They have also been responsible for thousands of dollars in fines by IRS for their wages against my SSN.
It has also affected my disabilty payments and job opportunities.
Have exhausted all government and law enforcment agencies to assist. Was told by all I need to hore a law firm to assist.
I am a single parent a d disabled American Veteran.