Hi Stephanie, We are sorry you are not satisfied with our unicorn and dinosaur pyjamas. Unfortunately we have to conform to the new US sizing guides which we do state on our cosy knit pyjamas product page. A US size 10 would be a UK size 8-9 years, and a US size 6 is a UK size 4-5 years. If you would like us to exchange both your cosy knit pyjamas please let us know. Thank you, Krissy.