Buying a golf 7 gti under false pretence

Traded in my vehicle on a golf 7 gti after receiving countless emails from the sales man David Liversage about the vehicle having a performance chip approved at a vw.the dealership principle himself agreed on this as it was he's wife's car before she traded it in apparently long story short with having all this emails and making up mind based on all these extras the vehicle has I buy the car I then .take it to a performance chip place to verify what the dealership has told me only to find its non existing.call the dealership after 2 days they reply on email that they have made a mistake after putting this on email in writing to me saying that the vehicle has this specific plug and play chip.the dealer principle then tells me he's not sorting it out I can do what ever I want and go to my attorneys how can a place like imperial select george do this to people selling things under false pretence and then once they got ur money treat u like dirt