Dd had a major tantrum last night, part of which happened in the car. During the course of it, she grabbed the headwing area of her Parkway SGL and pulled forward and down on it sharply. I found some stress marks on the part of the seat that slides up and down. I have removed the back from the seat so she can use it backless for now. I want her in high back, so it will have to be replaced eventually. Is it likely she damaged the backless portion of the seat? Can I buy just the back from Britax? Am I going to lose my mind before she grows out of these $&:% tantrums?