Be reunited with my grandson

My grandson Jaycob is in custody of his Nana bcz the mother signed over her rights and Dad was incarcerated. At 1st Nana brought Jay to me (Nee Nee) 2sometimes3 days a week, and Jaycob+myself called 1another every evening. Until 1 day for no legit reason Nana stopped bringing Jay over, letting him call me and I was blocked from calling Nana's phone as well as blocked on messenger. This is depriving a Sweet Child Of Love his Nee Nee can and wants to give him