Woolworths Witchery Grey jersey

I bought a Witchery jersey a while back and after 2 or 3 washes it seems that with each wash the jersey has shrunk. It's a long coat jersey and as there are slits in the panels the panels in front and at the back are no longer hanging straight due to it shrinking. Even the sleeves have shrunk. I never wore the jersey after the last wash as I have to stretch it to wear it. and then it doesn't look right in front. Witchery is an expensive brand but when I returned it they said as I didn't bring it back in the 6 month period they can't take it back. A jersey isn't something you wash each time you wear it and I have also lost the slip. They can clearly see it's Witchery as the label is still there and the code they punched in also brought the item up on their screen. I was at Woolworths in Cavendish and they refuse to give me a refund despite it just me not being able to wear it at all. I have been one of Woolworths best customers as I have a Woolworths Store account, Woolworths Loan and a Woolworths credit card. I have never lapsed on any of my payments for the last 30 years and mostly pay more than Im supposed to. I hardly return items but this is totally unacceptable as it is clear the whole jersey has shrunk.