Will ST entertain this kind of issue for single user like me? Do you know how long it usually take to resolve?
Historically and in my personal experience with ST long ago, not really. Knowing ST business ethics I doubt they would have changed since then. If you get a response, it will likely be another back and forth with a clueless customer service rep. And you lucky they may finally forward your feedback to the network engineers. (Not sure if anyone else has any success in getting ST to make routing changes and want to share your experience here?)
Even if ST do resolve their egress routing issue going to USA or HK, the routes coming from Time to ST likely still route to HK which will bring your ping to 40ms at times, which ST will claim they cannot control. Although Time can solve the routing issues towards ST by forcing their routes out of MY directly instead of HK, this all stems from a very problematic network configuration on ST side that makes it hard for other networks to determine the fastest route. It has been eons but nothing was really improved about this.
Even so, we are not really sure if your game is really hosted on Time network. It will be nonstop chase to get ST to fix the routing as you may connect to other SEA game servers that may have the same issue. Rinse and repeat.
What you can do now while you are still stuck on ST is find a VPN provider and connect to their SG servers before gaming. But again note that even some VPN providers have the latency issue with ST for the same reasons.
With this, I appeal to all customers and potential customers of Singtel or Whizcomms who may be reading this thread to reconsider if you want to be stuck with this crap network for 2 years

Times have changed, time to stop thinking of Singtel as a "high end" and the only reliable provider just because they are the biggest and oldest.