Ah second marriages and stepparents. It's always the same. There are exceptions, but more often than not it's a problem.
From the new wife's perspective, she wants her own family and doesn't want any reminders of her husband's previous family around. This is especially true if he has to pay child support. New wives see that as their money. They don't want to share anything with the old family - either time or money. It's obvious your daughter is not welcome there as far as she is concerned.
The interesting crucial factor here is the dad. When it comes to standing up to their new wives about their old families, husbands are pretty spineless. They don't want to rock the new boat. He probably sees what is going on, but turning a blind eye to it.
So, what can be done?
Tell your exhusband that you need to speak with him about the situation. Once you've told him, ask him for suggestions on what you are both going to do. If you are really concerned about your daughter keeping her relationship with her dad then you need to work something out with him so that he cannot use the excuse it won't work or he didn't know about it.
If there are court appointed visitations at set times you will have to inform the court of the situation if you can't work something out on friendly terms.
Keep your head and don't lose your temper. Don't make this a fight between you and his new wife. You will lose and so will your daughter. If you love your daughter and you want her to maintain a relationship with her father than you must continually remind yourself of your goal.
Good luck.