ON-AIR TV REFUSING TO CANCEL DSTV EXPLORER SUBSCRIPTION THAT WAS NEVER INSTALLED

On-Air TV Sales Agent called to offer me a deal claiming it was a discount, didn't explain in detail the billing associated with it, he sold me the dstv explorer decoder saying I will only pay 179 a month including the channels, I received the decoder on a broken seal and requested for an exchange and only recit after a month, I was told to pay even for the month I was still waiting for the new decoder..

I tried canceling the contract but they're not helping me it's been 4 months now, they keep on transferring me to various departments without any help, I feel harassed with their collection sms's everyday.