Child's Father Doesn't Answer When Called

We share 2 children and for the last 3 years he's been completely hands off and only pays child support.

His wife wants to see the children but I feel more comfortable with only having dealings with him as the last time she & I tried to work something out, I was lied on and he said "You act like you want your ass beat." Despite telling him I can prove his wife lied we just argued so I hung up. That's honestly the last we actually spoke on the phone.

Well, my children have been asking about their father and I'm wondering if I should make another attempt (with him). We call their father at least 1x a month to try and make contact. I hand them the phone once it starts ringing and I walk away. This way they have their privacy and won't feel like I'm hovering or needing to be nosey. He doesn't answer. EVER. No text back either.

Honestly, I'm torn because I know he won't answer but I know they still like to call hoping he will eventually.

Their ages are 7 & 4.

❗Thanks ladies.

@Meh...I said I would only prefer to have dealings with him and not his wife. Second I've tried that. He won't answer his text. The kids leave him voicemails. Either way we have 2 children, he needs to be able to co-parent. Period! That's what our children need, not him not wanting to deal with me. He had 2 kids with me. The split was amicable. He stopped coming around when he got married. Sorry, maybe I'm slightly offended at that part because I've done nothing to him but try and help mend his relationship with his children. They need it, not me.