Ah! Being fobbed off! I've never heard of mugged off before but the reference to the Urban Dictionary quoted by some other member here helped me know what it means.
It's down to the individual, isn't it? Some people are kind, approachable and helpful. Others like to take and not give, so fobbing you off may be a way of getting out of having to put some effort into it, when you're so used to taking.
I really cant see the point in being difficult or stand-offish but, unfortunately, some people can.