Unless there is proof that failure to pay a fine or that portion of the fine that is due is excusable, the court may after a hearing find the defendant guilty of contempt and sentence him to not more than six months imprisonment, if a term of confinement of that amount could have been imposed for the offense charged. If an alternative sentence has been imposed under section 9758(c) (relating to alternative sentence), the alternative sentence may not take effect until there has been a preliminary finding of non-indigency, and a willful failure to pay the fine.
42 Pa.C.S. § 9772