iPhone 5 Lightning Cable Burned

This morning I was charging my iPhone 5 via the lightning cable that came supplied with the phone on a USB port of my computer. I checked to see the battery percentage of the phone and I noticed it was still at 25% and not charging. I then checked my lightning cable making sure it was plugged in, and to my horror, the cable was burning up! I quickly pulled it out of the computer and threw it away.

I'm very concerned about this, as there was smoke coming from the cable top, and I could see that it was being melted. What exactly should I do? Now I can't charge my phone, and I refuse to buy another off Apple for however much it is. Do you think that this will be included in the warranty, and if not, how can I go about reporting this?

Thanks