Misleading Dstv explora decoder promotions from on air.

I had a normal hd dstv decoder and received a call from on air about a promotion they have regarding dstv explora. I was told I would get a new explora 3 only with an additional of R139 per month for 24 months. I asked repeatedly the agent no extra fees for installation, activation of explora features and so forth and I they said NO extra fees just your normal package fee and extra R139 amount for the decoder as even from the delivery you will get a voucher for installation for free. After a month after installation I receive a call and text messages about activation of feature I must pay extra R95 and extra amount for installation fee of R130. Please note these guys are misleading and I'm even worried they ruin people credit record.