I have just returned from Bali and I have 3 Mentari sim cards that I no longer want.
One of them has about 18 000rp of credit still on it, another around 5 000rp, and the third about 1 000rp.
They are all valid until the end of March this year, and can simply be recharged.
If you want them, or only the one with the most credit, just email me and I will post it to you with the phone number and the pamphlet with all of the instructions.
Mentari charges for sms between mobiles in Indonesia is about 500rp, and sms to Australia is under 1000rp.