Surprise by @DiGi_Telco response when I contacted customer service (took me 15mins waiting time to finally talk to one). The first person told me my lines are deactivated because the roaming charges were more than RM3,000 just in 3 hours while I was in Singapore. Before the customer service personnel could activate my lines, I must provide my credit card number.
When I found I was about to loose my temper speaking to the customer service personnel with such idiotic request, I said wanted to speak to his superior. Mohan, his superior took over the call and explained the following to me:-
1. DiGi is in partnership with roaming alliance in SEA and parts of Asia, in Singapore it is Starhub.
2. Starhub only passed the usage data to DiGi after 1 or 2 weeks, as the partner needed time to calculate. However, DiGi at that point of time, has no information that I was on roaming, more so roaming with its roaming partner. The system does not support nor generate such alert.
3. Although RM36 is the data roaming charge for daily usage, DiGi has no information nor any clue I was away, until Starhub pass DiGi the data in 1 to 2 weeks time.
4. I will continue to have this problem wherever I am on roaming.
Mohan also told me that DiGi has activated my lines again while I was speaking to them, they forgot that I activated the lines myself, via self-service menu.
I am going to check with other telcos whether this would be the case whenever one is on roaming. It is highly inconvenience especially on eis told to select Starhub to enjoy the rate.