tresemme treatment awaitng for 2months

On the 18th October 2015 I bought a Tresseme conditioner with treatment special advertised and was told there is no stock and gave me a receipt and was told to come back nextweek. Since then i have been driving to the shop but im always told theres no stock even after 2 months..i dont understand why a big company like this advertise promotional things and not have stock??? I paid the full amount but have not received even feedback on this. Im very unhappy as im waiting my time and petrol for checking up on a paid product that i dont have on me.