hi, im using digi, and so far i received calls from singapore (they r using starhub i think) and i didn't get charged for it.
as for sms, i do not get charged for the sms received as well.
dont know if this info can help u, but i think for our country we dont get charged for calls and sms from abroad, unless ur roaming.
Receiving International Calls and SMS, Sorry for being a n00b about this!