Even her parents did not bother to inform us or my parents that she leaving the country and what all actions can we take to get her back as my kinda are just 16 & 8 years we have expected her to return back after some time.
You cannot force her to return, at the maximum you can file a petition for restitution of conjugal rights seeking court's intervention to direct her to resume the broken conjugal relationship, but even court though may pass an order cannot force her to live with you against her wishes.
Now that they broke our trust, what all actions can we take on both her and her parents as they have cheated us and basically leaving a trauma to me and kids like this.
Legally you cannot take any action against her parents, especially cheating etc., She is not a kid that she was influenced by someone to leave her family and stay separately. Nobody can legally interfere in her rights to stay away from everyone. If you cannot digest her behavior you can file a divorce case against her and leave her outside without any rights or benefits out of her marriage to her.