Note to my friend please don't look

Dear Katherine,
     My sister said you were being mean to her today. Her story is that when I go to T-Rock with you,  you like to play with me more. I saw the hello kitty that said "Lilian and Katherine are BBF's." She felt like that isn't true any more and wants to throw it away. She wants you to be nicer to her and let her not feel lonely.  I know she once said you are her one friend that is not her sibling and a second grader.     

                                            Your friend,
                                               Benlin