Can I contest charges on my credit card from 4 months ago?

I had an awful customer service experience with videosilo.com (never ever go there!). They promise to convert old VHS tapes to DVD. I sent them my tapes, they charged my credit card, and i have now waited 4 months for my DVDs to arrive and they never have! The company lost my tapes, and has the worst customer service ever. They refuse to respond to my emails, and won’t reimburse me. I’m livid and want to contest the charges on my credit card, since I never received the product. Can I do this? Or is there a different way to report online scams…for example, what do people do when they pay an ebay user and then never receive the goods? That has never happened to me from an online purchase before, so I’m not sure…