Document every time she doesn't answer and your intent was to speak to child. Text her before and notify you are calling to talk to the child. Take screen shots of phone. Email her and tell her you tried reaching child on x days at x time. Attempt to solidify a specific time to call in the email and continue calling. It will force her hand and give you proof of her keeping the child from you. On your side though, when you do call to speak to child, do not talk about anything else with W.
I've been wondering the rules on this as well. My WW is like yours, selectively answering my texts on childcare issues. My S11 has a cell phone and when he was with me, I didn't want him to keep texting my WW all the time for small things. I told him to check with me first. When he's with WW now, I text him once in a while but I don't want to keep clinging on him either. Are we supposed to provide access 100% of the time to the other parents? How does it work?
Me-LBH, 48 Spouse-WW, 48 Married for 19 years Son, 12 BD #1 - November 1998 (EA 7 months after wedding) BD #2 - November 2015 (same XBF EA) WW filed D February 2016 WW moved out April 2016