Turtle beach mic help

I just bought a DPX21 headset off ebay with the description "perfect condition" and I get it and it sounds great but the mic doesnt work. I have checked my accessory settings and the input and output both read Turtle Beach... I have tried a few different data cables with no success. I have the chat switch on. When I mute the mic, my chat symbol pops up for a second as my old mic would but I can never talk into it. Any suggestions would be helpful before I go leave a negative feedback.