Unavailibility of products advertised

I ordered a new data device (router) from Vodacom around the 17th of February 2015- I phoned a few times since then but they are either off-line or I am being told that the router is out of stock - no other options apparently available. They gave me a tracking number for the couriers - the couriers did not even receive the router as yet - I phoned Vodacom again a few minutes back to once again be told they are off-line and I need to phone them back later or they will phone me back(this is already 1 month later). If the router is for such a long time out of stock shouldn't they advise me of an alternative? Is Vodacom not suppose to remove items they cannot supply from their items advertised to the public?