Advertise good deal but don't deliver!

After seeing an ad for a Huawei E5573 Mi-Fi Pocket Router on a Smartdata 5GB deal for R99pm*24 I went to my local Cell C store (Eikestad Mall in Stellenbosch) along with all the required FICA docs etc in order to sign for the contract. This was 2 weeks ago. They then told me that they're out of stock but they expected their new stock by latest the end of last week and that I can thus go ahead and cancel my current Vodacom contract in the meantime and they'll then inform me as soon as the new stock arrives. I then cancelled by current data contract but didn't hear from Cell C until this morning when I phoned to follow up - only to then be informed that apparently they cancelled this deal in the meantime?! This without even informing me - even after I clearly ask for the worst case scenario in terms of by when the new stock would've arrived so that I could make an informed decision in terms of by when I needed to cancel my current contract! VERY FRUSTRATING to say the least! Stop advertising deals that you can't deliver!! I also find it interesting that the size of their monthly booklet that can be downloaded is a massive 13MB... why that big?! They must be making thousands of Rands each month just based on their clients downloading that... don't think that we don't realize these types of principles! I'm sure most people out there would, just like myself, not support these kind of ethics!