I order a PC. Vendor happily takes my info and CC number. Few days later, no shipment information. Call vendor. They say it will be there in a week. A week later, no PC, call vendor. They say they have no idea when it will ship. I say cancel. They say, OK, but we have to charge you 15% restocking fee. I say "you're nuts. You haven't shipped anything, how can you charge a restocking fee for stock you never had? Cancel my fucking order." They say OK. I buy PC from other supplier and it arrives in a few days. A few days after that, I get a PC from the original vendor and find that they charged my card after all. I call Citibank, tell them the story, Citibank immediately reverses the transaction and tells me to send it back at vendor's expense and send them a copy of the shipping paperwork.

That's why you need chargebacks: for fuckwad vendors out to rip you off.