In Reply to: there is a number posted by wss on Saturday, 21. February 2015 at 22:40 Bali Time:
There is also a "My Telkomsel" Android app (not sure about iPhone, possibly as well) and it is available in dual language, so you can set it to English.
You log in and it lets you pick from/buy all the different data plans available, transfer credit to other Telkomsel customers, view current promos etc. There is also an app for XL if you choose to use them too.
It's much easier than navigating the old school menu that's only available in Bahasa Indonesia