I’m having trouble getting through to Singapore Airlines, maybe because it’s Saturday. Perhaps that’s why you had problems, too. They’re shut tomorrow (presumably in Bali as well); so I’ll have another go on Monday.

However, your Monday comes seven hours earlier than mine, and I suggest you go to the Grand Bali Beach Hotel in Sanur, after 8.30am, where all airlines that serve Bali are alleged to have offices. Even if Singapore Airlines isn’t there, you will be able to ask Quantas or someone else for an up to date phone number or the SA office whereabouts. Some other airline might even be able to change your ticket for you.

The Grand Bali apparently has ludicrously high internet access costs; the Santai Hotel is better, according to my book. I’m sure there are other places.

All I could find online is that there’s a SA ticketing bureau at Denpassar airport.

Tel: 0361 768388

Airport Office
Address: Ngurah Rai International Airport
Jalan I Gusti Ngurah Rai
Denpasar 80362
Bali
Indonesia
Operating Hours: 0900 hours to 2100 hours