Misleading information

A representative of On Air contacted me for a special package deal they were running. It included a R3000 installation voucher, a new Explora Decoder etc. R79 per month. When I inquired about my installation voucher I was told that it is only for R1250. I was informed that I could cancel the contract due to misleading information. The decoder was collected, but they are still deducting a debit order from my bank. I paid for two months now, and never even made use of their service