Advertise something they don't have

Few days ago I went to the telkom branch at mall of the south,saw a laptop I was interested in,price was R249 & comes with a free router,upon requesting to purchase the item the consultant tells me he'll give me the item with a different router for R279,he tells me the router which is advertised,they did away with it yet the advert says the special is till end of March,so I don't know who's lying,I went ahead & took the item but don't see how it's my fault & why should I be paying R279 cause I was interested & only willing to pay R249 or could of just took the laptop without the router but was never mentioned to me by the consultant,Would like it if something could be done to my premiums or my deal I took can be changed