I actually am having mine replaced, I received my MBP back April of last year, still have 30 some odd days left on my warranty and Apple is shipping me out a new one free of charge 🙂
The deal with mine is it started acting up as if when plugged into the laptop, it had to be held a certain way, or in a certain position, or else it would not charge. Frankly I didn't like it, and with a programming class coming up, I cannot risk it, luckily Apple will replace ANY charger from the "Mag Charger" deal that has issues because they were sued, so they wont ask questions but merely want a credit card in order put a hold of $70 when they ship out new one, then lift the hold when they get your old one back
At least thats what the apple rep told me tonight over the phone, i did get receipt and it stated $0 will be charged so long as they mine back.
Call Apple they will send you a new one.