What are the chances to void joint custody and do I have any way to stop it from happening?

My ex-wife and I have two children. We have split custody. With her being the primary, she has often not consulted me on major decisions like school, religion and medical information over the years. I have to admit I have not seen them as much as I should have over the years due to distance. I live in another part of the state, three hours away and before that I lived six hours away. I am making a lot of effort now even though it isn’t possible to get them every other weekend as I pay child support and the distance as well. Most of the time, she won’t answer my phone calls or texts about getting them. I get them on most big chunks of time like summer vacation, Christmas and so on. My parents live in the same town as her and get my kids on my weekends when I am unable. I stay connected via video chat and phone calls with my parents when they have them. I ended up filing a contempt paper with the court after she continually would not make an effort to keep me informed or return my calls about visiting. I even showed up at their school and the school would not let me see them until they cleared it with her. In response to receiving the contempt of court notification, she has gotten an attorney and is now trying to take away my joint custody right stating it is in the best interest of the children because I have had minimal contact with them and because I live three hours away while still wanting that child support money and is also trying to get me to pay her legal fees to do this.