Customer service sucks!! Poor quality clothing!!

I'm absolutely seething with Pick n Pays customer service. I purchased a dress from Pick n Pay clothing over a month ago, I wore the dress, there was nothing wrong with it. So like a normal person would, I pulled the tag off... there was no need to keep the slip, as it fitted perfectly. Now after 1 wash, I cant even get my arms through the sleeves.

So according to customer service, if I don't have my slip or have a smart shopper card to prove my purchase, they cant help me? What a F@#$ing joke!!!! So I lose out on an item that clearly has a pick n pay logo on, because of THEIR poor quality?? But wait, they appreciate my call and will log my complaint with the suppliers as this is feedback they need!?!?! How the F@#$ does this help me?????? How is that customer service???????