Who does she think she is????

OMG! I am pissed off! My Ex's new wife seems to think that she can decide when my kids are going to come visit me! And then to top it off she is going to tell my kids when they are coming and why they are not coming when they should!!!! First of all, she has no say in when they come and don't come! And even if she did it is not her place to be telling my kids these things! I understand that she is now in integral part of their lives and that I have to live with that, but she has no say in what happens with them! That is mine and my ex's decisions not hers!!!!