It is rather simple.
Any crime can be prosecuted by the state and if you are put on trial by the state, you have to show up to court.
The Muslim court cannot prosecute you.
If somebody wrongs you, you can sue them in a real court, or you can both agree on mediation.
If someone sues you in the Muslim Court, you do not have to show up, but you can if you want.
That presupposes you have the freewill to refuse. . .and if raised a muslime (especially a female muslime) you have no power to refuse. It is not “voluntary” in any way. It is mandatory.
You can NOT have your muslim courts here. What part of "NOT" do you not understand. No.