AllergyBuyersClub / Do not purchase from them

How is this possible to make your customers pay for your own mistakes?
They sent me a wrong product and I wanted to simply exchange it. they made me pay to ship it back. It's just unbelievable.
Their website doesn't say anything like this, so people just have no idea that they will be charged for mistakes they didn't make.
Why is it so hard to take responsibility for your employees' actions?
I sent numerous letters to them and got nothing back. Wonderful customer service that will irritate you to the maximum.