More details to this question:
defending lawyer filled a cross-motion to challenge certificate of due diligence and disregard amendment to answers to interrogatories for failure to comply with rule 4:17-7
1 ANSWER
If your attorney's representation has not been up to professional standards of competence, and his/her incompetence has caused you damages, you can sue him/her for malpractice. However, what you've described - defendant claiming that plaintiff has failed to live up to some procedural rule or other - is just business as usual in a litigation. You haven't even said that the motion was granted! I don't see any basis to sue your attorney.
Answered on Sep 11th, 2014 at 1:05 PM