My NIW lawyer (he is not really a lawyer, since he does not have the certificate)and I have some dispute about our contract. He did not write cover letter as he promised, instead I wrote it by myself (he provided the sample letter). Anyway, my I140 got approved. However, I do not think it is fair to pay him for the full payment ( I alredy paid him half). My question is -- is it possible that he can do any harm on my approved I140 or pending I485?