It sounds like you need to file a Motion for Contempt against your ex-husband for his failure to pay the court-ordered child support. You may want to consider requesting that all future child support payments be done via an income deduction (assuming that your ex-husband is employed). With the income deduction order, the child support will be taken directly out of his paycheck. As far as claiming your son on the taxes, if you both have claimed your son, the IRS will likely look into it if both of your taxes show your son as a dependent. Without knowing what is specifically addressed in your divorce decree regarding the taxes, I cannot state whether your Motion for Contempt should include the taxes issue.
You can file an application for contempt for his violation of the Court Order. You can also file for a continuing garnishment or seek an income deduction. If you have your son more nights than the father and did not agree to let him claim your son as a dependent, you are entitled to claim your son. The father should be advised to amend his return so that you are not both claiming the son.
To obtain sole custody of your son, you would need to speak with an attorney in your area to explain the facts and get an opinion regarding the possibility and probability of changing custody. It is not totally clear what you have in mind when you ask what you can do about "getting sole custody". There is legal custody and physical custody. Most people think about custody as physical custody. When you talk about "getting sole custody", are you talking about simply reducing the father's parenting time or eliminating the parenting time?
In almost all situations, you would not be able to eliminate the parenting time. This is because the Courts view it as important that both parents have a relationship with their children. If you are talking about reducing the time for some reason, the parenting time/visitation could be modified without changing the custody to "sole custody". Again, you should consult with an attorney.
Legal disclaimer: In answering your question, my law office and I are not undertaking to represent you, and you should consider hiring counsel to assist you. The answer provided is based on brief and limited information and therefore, there may be facts that would alter the answer provided.
To collect the past-due child support, you would need to file an action for contempt against your ex-husband. As has been suggested, you can obtain an Income Deduction Order to ensure that future support is actually received.
To obtain sole custody, you would need to file an action requesting to modify custody. In order to modify custody you must show the court that there has been a change in circumstances since the existing order was issued, that the change makes a modification necessary, and that the modification you are seeking is in the best interest of the child.
Under federal law, only the custodial parent has the right to claim a child on their taxes. The non-custodial parent may only claim the child if they have obtained permission from the custodial parent to do so. State courts are generally reluctant to deal with tax issues. Therefore, you should contact a tax attorney regarding your rights related to his violation.
~ Kem Eyo
The above answer is a general explanation of legal rights and procedures. It does not constitute legal advice. Nor does it establish an attorney-client relationship between the individual posting the question and the attorney providing the answer.
You can either ask the state child support unit to assist with collecting support, which will be free, or pay a lawyer to sue him for contempt, or use an abandonment case to jail him for non-support.
Who claims your child should have been addressed in your divorce papers. If he did not have the right, go to irs.gov, report him on their fraud phone number and not only will he get audited but you may get a reward. You should claim the child yourself if you were entitled to.
Nothing in your post shows a reason to seek sole custody. If you feel there is a reason, see a lawyer.
When did you divorce? Have there been any prior modifications?
Child support: Is there an Income Deduction Order? (IDO) If so, is it effective immediately or upon a month's delinquency? You can seek a contempt hearing for that either immediately or after a month, after a notice to his employer of delinquency. If no IDO, you can still seek a contempt hearing for the nonpayment of ordered support.
Taxes: It depends on what your divorce ordered to be done regarding the taxes. Did the order say you split the return, claimed the child(ren) in alternate years, or did one parent get to claim the child(ren)?
Sole Custody: What kind of custody are you referring to? Physical? Legal? Both? What kind of custody do you have now? I'm assuming it is joint. You would file a petition for modification of custody, but the court will need to see a material change in circumstances.