I went to sg early this month, just received my bill and their charge me 650kb of data roaming usage but i confirmed that i did not switch on data but switch on the phone to receive call and sms.

after i made the complain, they called me back that they will waived it for me because some issue on smartphone with lte trigger the network. She said the network will auto trigger the phone even though u switch off the data and she also said, switch off the phone also kena.