My adapter frayed a while ago. I called them up and they sent me a new one, without requiring the damaged one to be returned. Unless you actually wound the cord around the prongs, I doubt they'll have a problem with replacing it. Basically, for an adapter, it's a no questions asked replacement, since they are probably one of the cheapest service costs for them.
I had the adapter within two days, except I had one of the yoyo style adapters originally and they sent me the square model with neither a wall adapter or extension cord, even though I explicitly told them I had the old style, the extension cord of which would not work with the new adapters. So, they promptly sent me an extension cord, for the yoyo style adapters. So I had to call them again and say, no that's wrong I need the extension cord and wall adapter for the new power adapters. They finally sent me a wall adapter so I could at least plug it in, though they still didn't send me an extension cord (I've found that the extension cords for some electric razors, slow cookers, and hp printers make good substitutes). Amazingly, it took less than a week to work through all this