I am not sure, but when I got mine I just took scissors and cut the bottom flap (where you plug the cord in to charge it) off. I find it unnecessary anyways because I am constantly charging mine and listening to music so it hasn't bothered me at all!
The "warranty period" described on the OtterBox website specifies that it is good until up to 1 year after the date of purchase. This is pretty standard for most products. You can read more here: http://www.otterbox.com/warranty/warranty,default,pg.html
I don't think it has any kind of warranty especially if its a fake otterbox. Maybe if u purchase one from the otterbox website it comes with a warranty. I haven't been told about a warranty with the ones or purchased on here. I would just suggest getting a new one but be careful who u buy from. There are a lot of sellers selling fake ones.