There is no need of data leak. Name, IC number, phone number, address etc is what you filled in if you enter contest last time (now more online). So, these info is lying everywhere and one can just sell them. These info are not very secretive anymore.

Yes. Had similar call many years back.

Someone pretend as bank officer (a bank in Ipoh) and even telling me his name (Malay name), but I could hear certain part he slipped a hint of Chinese accent. He asked my name and also verified my IC number. Correct. I think it was to verify the charge made or new application, I could not recall.

I said I did not have account in Ipoh and no CC from that bank. I told him that since it was someone else using my IS then just do not approved it. Then he told me to make police report. I asked him why I need to make police report since it was my problem (for me it was bank problem ). To end conversation I just told him that I'm busy shopping now and asked him to call me back after 2 hours.

Surprisingly when I was home 2 ours later, I get the call again. I just let it ringed when I saw the number

I think using Truecaller or whatever, it just blocked all the number being labeled as scammer. However, those scammer are using devices that send fake number. The number can be valid number belong to someone else.

Not really. Phone rang and my phone showed Possible Scam. I answered. Said hello but no one answered and after few seconds said hello again and when I was about to hang up, got voice from other end. It was Astro calling to inform about broadband package for Astro customer. It was a legit call.

I think nowadays call response sometimes a bit delayed due to voice call is now processed through packets, VoIP, in telco network system. I'm assuming this. Even when I received call from my brother it happened from time to time.