keycard problem?

I don't no much about these keycards but I will try an explain my problem...the keycard open the doors and that's it, no lights on the dash.. nothing, it did work for one day, i brought the car from some bloke selling on gum tree, him in London me in Folkestone all I had was his phone number...I called him about the issue and he hung up and blocked my number...so does anyone know anything about no lights on the dash...I cant even start the car, electronic handbrake so cant even push it to a garage I have been well and truly done over...unless it is something simple...bit like me I suppose