When a witness at a hearing testifies "no, that's not my signature," and you can "very easily" prove that statement false, the time to do it is during the very same court proceeding.

You are responsible for ensuring that your own witnesses appear for court proceedings. A party may choose not to call his own witnesses.

Beyond that, as Xena notes, you're being too vague for us to be of any help; run the facts past a local lawyer.