Please Cancel this contract

I asked for a 60GB router, which was delivered on the 18th of April, on the 19, and every day since then I have reported that it isn't working, and I am unable to connect. I have had no real help from MTN. I wish to cancel this contract because I have been sent from pillar to post with no real help. Floyd continues to ignore my request and I am feeling frustrated and dissapoined by the incredible lack of assistance.