VGA to HDMI??? are you sure? Is it a branded cable??
Because HDMI carries a digital signal whereas VGA carries an analog signal. So I am not sure if this is possible. That is why there are these conversion boxes which convert the signal. I know from personal experience that HDMI to DVI is possible and works (albeit without audio). Does your laptop have a DVI port? If it does then get an HDMI to DVI converter/cable.
If your HDMI to VGA cable does not work (and I don't think it will work!!) then take it to the shop and make them demonstrate how it works.... if they can't do this then ask for a refund.
Because HDMI carries a digital signal whereas VGA carries an analog signal. So I am not sure if this is possible. That is why there are these conversion boxes which convert the signal. I know from personal experience that HDMI to DVI is possible and works (albeit without audio). Does your laptop have a DVI port? If it does then get an HDMI to DVI converter/cable.
If your HDMI to VGA cable does not work (and I don't think it will work!!) then take it to the shop and make them demonstrate how it works.... if they can't do this then ask for a refund.