I made a police report on the number, and using the police report, Starhub and Singtel did a phone tracing. Some prank calls came from different locations, so a letter was sent asking them not to call anymore. This number stopped calling for about a month, before it resumed again.
It turned out, according to the tracing, that this phone call originated from the "Bukit Panjang" area. Another thing about this call is that if it called my house, I can't cut off the conversation unless the other party cuts off. I can cut off the phonecall with my handphone, but with the house phone..
Going to do another plice report. My Dad and I have been compiling all the calls this caller went to my house and handphone. Seriously, I don't know this person, and I have nothing to do with MINDEF (if it comes from there). Hopefully I can bring this prank caller to court this time.