Zolucky Clothing review: Return

I ordered a shirt is a size XXL. They sent me a S. I contacted them to return the product and obtain the correct size. They asked me to take a 15% refund and not return. I balked about this and said no. Then then sent me a policy showing ALL shipping costs for a return, including custom or boarder charges, must be paid for by the customer. Then then told me to take my 15% refund of $4.72 and have the item altered. They made the error and refused to make it right. How am I supposed to use $4.72 to make a shirt three sizes bigger?