7.2Mb is the download speed for local data if I am not wrong.
Which means, the data you are downloading may be purely
overseas and does not exist in Singapore / Local caches.
Try checking your speed out on the speedtest websites
eg www.speedtest.net
If its still 21Kbps, give starhub a call/complaint.
Complaining is how Singapore works... a nice conversation
would simply slip out the other ear. A bit of shouting is
helpful to the memory retention of some of the middle managers in
these companies.