Coussin Color Color

Picked this pillow because I loved the brilliant color and it matches my porch colors beautifully but the problem is the measurements listed are not correct! It says 18 by 18 and the pillow is so small it actually measured 15 by 15!! I was so disappointed because I love the pillow but looks too small for the chair and now I’m stuck with it unless I want to go through hassle of mailing it back! Manufacturers need to put correct information on measurements for the customer!