Miss Serene Tay, 38, was waiting in her Mazda 3 outside her cousin's house in Johor Baru on Sunday.
They were supposed to go out.
But the afternoon turned to horror when a motorcyclist smashed the front passenger window.
He then punched Miss Tay in the chest as she tried to keep her belongings away from him.
She lost her mobile phone and her wallet, which held about RM1,500 (S$600).
This is the third time Miss Tay has been robbed in JB.