I have had my grand daughter every other weekend for the past 14 yrs now her parents are using me as leverage to control her and won't let her visit

The facts are a bit unclear and that maks it hard to be precise.  If there was some memorialization of a formal status of a grandparent to the child by agreement or court order, Nevada case law says that such custody or visitation cannot be unilaterally terminated without further agreement or court order.  If not, parents not found to be unfit have the right to control who a minor sees, and how often.  There is a statute as to grandparent or other "third party" visitation, but the bar is pretty high.  Much more detail can be found here.  You do not provide any details about the parents.  If in doubt after reading the material, make a consultation appointment with a family law specialist who can go over all possibilities, costs, risks, and benefits.