I did not call the technician. I called TM 100 and the staff told me that I gotta pay rm200 for the new router + RM53 for the technician to come over and replace the router. So I went to my storage and turned out I found my old powerline kit from a few years ago and it works perfectly

No the router works fine, but I think because it cannot penetrate through so many walls at my house (probably cause it's a cheap wireless N router, thus the range it can cover is limited), the speed that I got on my PC using wireless adapter is only about 15 out of 30mbps. So I used my old powerline kit adapter (those adapter that you plug to your power socket and from it you just plug your ethernet cable) and I got full 30mbps since the connection is no longer connected through wireless connection.

This is the powerline adapter kit I was talking about