Ideas:

1) Use only a documented/written form of contact such as email to communicate. Keep messages short, direct to the point, and only about co-parenting.

Example: "I'll be there to pick up [child] on May 23rd. Please have [child] ready to leave at 9am. I will not stay to talk with you. If there's any new/pertinent information related only to [child's] care, reply here. I will only respond to respectable and relevant messages."

2) If they are abusive, harassing, refusing to let a parent see the child, refusing to respond, etc. you then have the evidence. Take it to your legal system. Establish your rights and take every responsibility to fulfill them.

3) Boundaries. Get some. Do not bend them. It's the only way to deal with co-parents that act like immature jerks. Once they learn that such dramatic behavior is not tolerated or acknowledged, it will become less prevalent.