Click2Sell used to be a reputable service provider, but now the are actively supporting scam.
Vendors advertise with a money back guarantee and sell through Click2Sell and in the checkout screen, the payment options are usually limited to PayPal only. At the end of the Clich2Sell purchase confirmation you receive only after you paid, they actually tell you that you just have been scammed:
"Note: During this product order and transaction Click2Sell acts only as the shopping cart/software solution provider. Click2Sell is not a seller of this product and is not responsible for refunds and/or returns. Thank you for using Click2Sell service."
Click2Sell doesn't even reply to refund requests and PayPal, as usual, takes the vendors side in the dispute resolution process. So unless you already know the vendor and know you can trust them I would recommend avoiding buying through Click2Sell.