What do I about my friend? (Did something mean!)?

Ok so im 12 and my friend is being a jerk. so we are best friends and have been for 6 years and in februeary her dad got 4th row tickets to Taylor Swifts concert and she invited me to come. Then FIVE months later (Now) she says she asked her dad and says i can't go now because her dad said no. And now i can't go at all and she knows how much it meant to me. Normally id be mad at her dad but its just when she told me she was like "Oops too bad ha ha you can't go! oh well " And that made me really mad. So i sent her an email telling her how i think that was really mean. And the next day I had to babysit my younger brother and he went out to play with her younger brother. I went out there to tell him to come home and she was just being a jerk asking why and making up excuses to let him stay out there. She also was calling my pet dog mean names while waiting at the door for my brother to come out. She also ding dong ditched me. then later i told him to go in for a second time after i let him go out there again and she was acting like im so mean making him go and asking things like "What's she making you do now?"What shoud I do? She makes me want to scream or cry or yell at her!