The Issues of mother running away with kids without the knowledge of the father demands an end NOW!

I kept my kids in the custody of my mother, cause the mother which gave birth to the kids for me was running away from the house we are living and leaving all three kids alone at home then i took the kids to my mother for the kids to be there for some while so i can able to go to work and make some fund, but coming back to my mothers house to check on my kids my mother said to me she showed up in her house and took all three kids and pass the back door of the house and ran away from the house. over 8months now i have not set my eyes on my kids. I need help on this situation of mine to asking my mother where are my kids. refuse to let me set my eyes on my kids, She's responsible for everything that has happen to my family and my dad.