I do not have your situation, but I can only imagine what it would look like:
Grandparents come to the door to pick up very small children. They give a terse, short hello to you as their mother, asking if extra clothes are in the bag, etc. No kisses, smiles, or hugs.
Children sense the tension. The next time, they see the same thing. If they do get close to the grandparents, they will want them to come in...see their room....play a game. More tension when the grandparents say they must go quickly.
Eventually, the children will really wonder what this is all about. They will ask questions such as, "Why don't you talk to Mommy?" or, "Don't you like Mommy?" They will have no choice but to tell them that you are in some measure "evil" or not approved by God.
I am so sorry this situation has come about for you. Your parents have been given a gift-that of children and grandchildren, and could have wonderful family times. The downside for them, of course, will come later in life. They will have ahunned their child, and eventually maybe lost contact with their grandchildren.
When they get older, when they can no longer care for themselves, the elders at the KHall will no doubt tell them that they have "family" who have the obligation to care for them, which of course means you.