@darnell weird, noone I know uses iMessage (in Singapore/Asia).
WhatsApp is super reliable (and you can call freely internationally or do video calls; quality is also good).
I think I prefer FaceTime for calling the parents in BE from SG, because of the iPad app and the quality is a bit less grainy over long distance; but for everything else, Whatsapp is #1 here, and Telegram likely #2 (usually is the more spammy/anti-gov/dodgy corners).