New Decoder not picking up HD channels

I have sent Multichoice countless emails i have went into the multichoice store and phone the call center many times but no one gets back to me or no one can help me I bought a single view decoder the 5 series i cannot pick up any HD channel all are in SD, even if they need to be in HD i am not sure why Multichoice releases hardware with no training provided to there staff on how to support it