Faulty goods on warranty but don't want to refund or repair.

I purchased a pure pleasure electric blanket from hifi corp and in 2 weeks the electric blanket gave up on one side. I paid R800 for the blanket and now they don't want to refund as the company says there was a crease on the blanket. Do they really think we are kids and jump on electric blankets. This is a 2nd pure pleasure electric blanket that broke so quickly. The blanket is on warranty as it's 3 weeks old but don't want to refund. Stay away from Hifi corp as their stuff is always faulty. I did buy 2 fans this year and had to return 1 as it was not working. Cheap but is it worth it?