Cheap quality clothes at high prices

I recently bought 2 summer dresses from woollies,and I wore 1 and I washed it only once and it is now shrinked I can't wear it anymore because it's too short and tight.i am even scared to wash the other dress and I don't have a receipt.why would woolworths sell cheap material at such high price.its wrong what their doing to consumers.please advice what must I do with this dresses?