still struggling

[Jim1234]

I've been thinking about how to protect myself without issuing ultimatums, and have a question.

We are stuck in a cell phone plan for another year, and agreed she would reimburse me for her cell phone. We also agreed that I'd keep the family plan at the YMCA, and she would give me money for that. She hasn't given me anything since she moved out in April. When I've brought it up, she whines about how the alimony and child support are less than her lawyer led her to believe it should be, and she didn't appeal it... etc.

How do I get her to reimburse me for these? My first inclination is to say "Give me the money you owe me or I'm going to cut off your cell phone and switch to an individual membership," but I have learned that would be a bad idea in my situation, i.e. another ultimatum.