Unsatisfied customer

I ordered a product and sent it back because I wasn't satisfied with it. Instead of me getting my money back I was told they will credit me for my next purchase, who said I wanted to ever order from them again? anyway in order for me to retrieve my money back I decided to order again (reluctantly. only because I was forced by that unfair policy of theirs, about crediting instead of refunding). The problem is how do I get my purchase credited? I can't call them because there is not number on their contacts. I googled but the number I find seems not to be working. After I manage to get this order in I will never again.