After long consideration, I decided to give it 2 stars (initially 3). I booked my departure time at 245pm. But no one told me if it's Thailand time or Malaysia time. I wanted to call the agent, Billion Star express but the hotline number stated in Confirmation letter is not valid.
I decided to go to the boarding point to check out earlier. However, the address seems unclear and I couldn't locate it. Hence I walked into another tour agency nearby. They were kind enough to look for the number to call. Hence, I would suggest one to call up Billion Star to confirm the exact pickup point before making the booking. The number which I searched online previously enable me to connect to their staff in Malaysia. They said will call back but never pick up my call after that. This is really frustrating especially when you are really lost and helpless.
The departure time supposed to be 245pm. However, it was delayed till almost 4pm. Despite the delay, we managed to get out from custom smoothly. Due to few car accidents encountered along the way, the driver decided to stop by at Gurun R&R. And he subsequently asked me to board another van as they were heading to the same destination. I was again frustrated by the slight delay of the departure due to waiting of another 2 passengers. But luckily the driver agreed to drop me at the place which is much closer to my home. Hence I really appreciate the flexibility. In the end I was 2.5hours behind my arrival time. My booking of early departure time becomes meaningless.
Overall, the 2 stars is to rate the bus company who does not provide clear communication on the time, pickup point and their hotline number (which I wonder it's 12go or the bus company's onus to update them in the confirmation letter). Besides, I do not have further comment on the driver apart from what has been mentioned above.