Question about contact with child.

My ex has full custody of our child. I have every other weekend and holiday visitation rights. Recently, my ex gave our 9 year old a cell phone. Do I have to allow her to bring it over when she comes to visit for the weekend? We have several ways they can contact her here, including a land line phone and cell phones. If they continue to send her over with her phone, can I confiscate her phone until she goes home, or am I stuck with her step-parent contradicting my rules through text?

Our parenting plan states:

'4. General Provisions Regarding Parenting Time

Each parent shall also have the unlimited right to correspond with the child, and may telephone the child during reasonable hours, without interference or monitoring by the other parent or anyone else in any way. Each parent shall allow the child to telephone the other parent at reasonable hours and with reasonable frequency, if the child wishes to do so.'

[tbyte]

As long as you abide by this arrangement, you would be within your right to confiscate the phone. Understand, though, that this is going to breed resentment from your daughter.
Perhaps a better strategy would be for you to allow your daughter to keep the phone, but require it to be turned off during hours that are unacceptable for calling.