Begin by giving grandma and grandpa the benefit of the doubt. Grandma had good intentions and thought she was buying something your child would really like. You can talk with your child and say something like, “That was very considerate of Grandma to buy you a phone. We’re going to have specific guidelines for how you can use it.”
You may want to limit the phone to be used only at home to call Grandma. If you feel your child isn’t ready for a phone, however, you may respectfully talk to Grandma and share a few of the reasons you believe the phone will be a detriment. You may want to recommend Arlene Pellicane and Dr. Gary Chapman’s book, Grandparenting Screen Kids. You can share what you’ve learned about the impact of too many screens on a child’s brain. Grandma may want to return it or save it for a later time.
If your child’s in middle school or older, you can establish rules before leaving the phone with your child. These rules might be things like charging the phone overnight outside of the bedroom and a limit of 15 minutes per day after school.