vs1502

Im working for a company A in USA and Im searching for better opportunities here. I signed contract with a Desi consultancy in USA but I didn’t transfer my visa and I didn’t provide them my documents. Weeks ago, I got an offer and rate was very very low . But I signed the rate offer and contract somehow. They said I have to take care of my visas (H1&H4) expenses. Then later I just realized that I cant pay that much amount and I said im not taking the offer. Within 2days I told them that Im not joining their consultancy. But they gave legal notice with attorney name. however I couldn’t see his signature, it was just a word document and emailed to me. I didn’t respond for that as there was not signature of attory etc. Few days later they again sent me the print out of same word copy without signature of attorney. Should I respond for that? Or are they simply threatening me? Please advise what I should do here. I am a legal employer of company A. I am not the employee of that Desi consultancy and I am not sure how they can do this to me. Please help!