Typically, an attorney will file a motion to withdraw, a hearing is set, and the court will relieve the attorney from further representation for good cause shown. Not being paid is usually good cause shown. I would seek alternate avenues to pay my attorney, as a good attorney is worth their weight in gold. I would speak with them.
Have you discussed this situation with your attorney? He may be willing to work with you. If not, he can file a motion with the court to withdraw from the case.
You have this under "child support" but I also see that you've commented that it is for a Criminal Case. If your attorney withdraws, the judge will typically then appoint the Public Defender's Office to represent you and the case will be passed for your new attorney to get caught up on your case.
This response is for general purposes only and does not establish an attorney-client relationship. You should contact an attorney to fully discuss your issues.