My one year warranty expired recently, a month ago my charger was replaced under warranty and it has only lasted a month and has broken again, does the replacement charger come with a new warranty or will i have to buy a new one?

Bought the phone on contract last January (late in january), had my charger replaced just after christmas and now it has stopped working again, its been about a month and a half and the replacement charger is broken, does the replacement charger come with a new warranty or will I have to buy a new charger? And if so, is there a charger that doesn't break easily (my problem is the the wire at the phone end of the cable seems to bunch and twist etc.)

thanks.