Misleading the client into buying a laptop

I bought a laptop form Game Brits branch. The sale person told me in front of witnesses that it can go on the Ethernet if I put in a sim which there Cleary is a port for. This is the reason I bought the laptop. After trying all three networks sim and no luck I returned to the shop. The shop tried also and with out any luck. After a promise that They will look in to it I left. I phoned Mustek the supplier of Mecer. The Technical department in formed me that there only a sim slot on this module There is no modem I need to buy this separately. Went back to the store and they said they will email head office. On the 21 September Game phone me an read head offices mail which said it doesn't have a modem THIS WE ALL READY KNOW .I told them they mislead me in to buying the laptop and demanded that they must arrange that this future must work on the laptop on there cost. The shop said they get back to me. Till now no one has contact me.