Sent to CSC for sensor cleaning. Ask them if the sensor is damage or not they said they did functional test etc. Looks good. Took some test shots again at f22, the sensor is clean again. Thanks everyone for the feedback and concern.
I am partly at fault for not checking thoroughly. I merely took shots at around f4 because the time of sales was at night and I didn't bring a flash. As long as no damage to the sensor I am ok with just $21.40 to clean. The seller does not know the marks as he got the camera from a CSer also not long ago.