The tests didn't work

I bought 2 different 4 packs from clearblue at walmart, and I went to use them and 1 of the 4 pack sets. It didn't work at all, it wouldn't do anything it wouldn't say negative, or positive, nothing changed on them at all. Is there a chance I can get a refund, for the ones that didn't work. I have purchased your product every single time I have thought I was pregnant, which is a lot because I have 3 kids, and hopefully will be 4 soon.