BEWARE OF DATAROAM UNLIMITED. YOU CAN STILL BE CHARGED ROADMING FEES EVEN YOU’RE YOUR CELLULAR DATA IS SWITCHED OFF.
Hopefully this will save someone's $ and time with SINGTEL.
I had a marathon 9 hours chat with their "customer service", with no less than 5 agents (no kidding!! I still have the thread on my WhatsApp). I waived the white flag for my own sanity...
My problem: I was recently abroad, and I switched off my cellular data / data roaming. I still got charged with daily roaming (SGD 19 / day) - for more than SGD 200 because of the Daily Auto-Roaming feature.
Trying to understand the problem...
Their roaming terms state: "Auto-Subscribe DataRoam Unlimited Daily automatically activates a DataRoam Unlimited Daily plan at $19/ $25/ $29 per day when DATA USAGE IS DETECTED on our preferred networks in over 100 destinations."
My phone cellular data was OFF and I thought that this will not trigger the daily auto-roam. I WAS DEAD WRONG!!
I was told about some "system" data exchange with the roaming operator eventually triggered the daily roaming fee, even if you, as a user, did not explicitly activate that data exchange and even with your cellular data switched off.
This is clearly visible in the daily data usage here: I used data roaming for the initial few days and then switched to using WIFI with a local card, resulting in a drop from hundreds of MBs to KBs. Frankly, who would want to pay 19 SGD per day while you could have 80GB for a month for USD 10…
Net net: after 9 hours, 5 agents, I still don't have an explanation as to why a phone with cellular data switched OFF can still trigger data usage, for which you get siphoned $19 / day. 1) This is frankly scary, and 2) it's a broad daylight deception (to put it mildly).
BTW, I read a similar note from "Simon Tham" on Nov 22, 2019.

My Mobile was renew on NOV 2017 and singtel give 3 months free a few subscription apps. I dont use the apps and had cancel it after the first month . on MAY 2018 my bill appear the 2 trial apps. This is ridiculous their billing system will just bill you although you cancel all your subscription so many month ago. This waste my time to contact them explain to them and they only say we will request to wave.
I must check the singtel bill every month , I m not sure what else will come out from there. Please all be aware.