How to disable the inmobiliser for Lexus is200 or get it remove?

I"ve recently bought a lexus is200 but after repaint,the garage lost my only key n the dealer of lexus can't help cause mine is imported type.so the garage do find me an unused is200 lexus n they shift all the ecu,anti theft,ignition switch n try to get it program but still can't be started n with the launch x431 we try to scan an still the code there UNMATCHED KEY CODE.anyone can help as long i can get it started.THANKS!