Advertising items they don't sell

I went online looking to buy a afrox gas without a gas canister, well it was available for almost R600 9kg, last time I checked they told customers that they have excellent online service...to cut long story short I was unable to buy it, then I went to Kempton park branch I asked the cashier at contractors counter then she sent me to frontline which I don't understand since I could buy it there, then I got to frontline I was told "We don't sell gas without the canister" STOP MISLEADING PEOPLE, By advertising things that you don't sell just to make more people to visit your store where there poor service.