why they hate me??

maybe you are trying too hard. children can be funny from an early age and they know exactly who they like and dont like. dont try too hard. treat them occasionally to something nice but not all the time. maybe you speak too loud and that scares them. its hard to know as you didnt mention their ages but stick with it and they will come round. even if they are never close to you at least you will be able to have some sort of a relationship.