I’ve been fooled time and time again but this is the worst. The seller simply ignore my pleas thinking I’m a docile person that I’m not going to report him to SINGTEL or other relevant authorities
I am not sure what Singtel would do if any thing. It is such a large company I don't know who or what department would handle these things. Getting Singtel attention is a challenge by itself. Getting someone there to listen to your story is a challenge.
File a claim with the small claims court seems like the best way if you have a receipt. Pay $10 filing fee and do it online. The merit of your case depends on whether you bought it before or after 26-11-2018. Before this date it was legal to sell this. After this date all the court says is the ISP would block the apps. How you argue that you are entitle to a refund and what the court decide remains to be seen.