I think you will need to personally serve those documents on your grandchild's mother not the child. Do the orders name you as the custodial party? If so, I would be prepared to remove the child or children from the mother's care once she is served assuming it is consistent with the custody order. I suspect this will not go over very well and you do not want to give her an opportunity to run or avoid turning your grandchild over.
Was the child's mother not at the hearing(s)? She should have been given notice of the litigation as she is entitled to notice.
Has the child been residing with you primarily or with mom? And when you say you have "legal custody documents" what exactly do you mean? Did you adopt your grandchild? Or did you file a suit to Modify the Parent/Child Relationship? One final question - when you were in court, were you represented by an attorney?
Unfortuantely, as you can see, there are numerous facts that are needed before an accurate answer can be given. I highly suggest that you contact an attorney in your area. Best of luck!