I don't see what Q has done the same as Sky, Virgin, BT etc.....offering incentives to get new customers, totally different business.
Q are advertising this offer on Facebook and on certain newspaper website, could be others, that is the two I have seen so far.
If a company chooses to send out offers to existing customers then they do, we don't all know what offers they send, for example, myself and my mum often get different offers from L'Occitane and a friend gets a different one again, however if you go on their website and they have an offer on then it is available to all, it doesn't say "only if.........." so for Q to have it stated on their website that new customers will have postage refunded is an ill thought out idea!!!!