The phone call starts with an automated voice speaking in English first then Chinese. It talks about I have an important piece of document still with DBS that you didn't collect/see/notice.

After that, you press a number and they connect you to the 'customer service officer'. They will then ask you for your name to check your information in the system, and tell you that you have a bill that you have yet to pay or a transaction from your credit card that isn't made by you. After that they'll ask for personal details.