FlexPay denied, but debited my card anyway

HSN should be out of business and sued by every legal entity there is. I placed an order (first time with HSN) for a laptop, entered a discount code, selected flex pay and was denied. But this evil organization did indeed charge my debit card for the first flex pay, then the message on the order page stated: you are not eligible for FlexPay at this time, would you like to pay in full.
No HSN, I wanted flex pay but you SOB’s charged my debit card anyway. Really!!
My money was credited back to my account within hours, but still, you HSN, have no right doing this to potential customers.
Take your FlexPay and shove it! I’d rather shop at Amazon Prime for better quality items and pay up front.
Shame on you for your business practices.