T phones do not work？？？

Why324 wrote:

I am from Singapore, I bought a T mobile phone on the shopping platform during the Spring Festival, the SIM card cannot be used, and the phone shows the SIM card lock inside the machine. Is this being deceived by profiteers?

nope..if they told you the phone is unlocked and it wasnt then the company that sold it to you would be the one that deceived you..if it was never mentioned about being unlocked then that sadly is on you for not checking.

Devices sold by T-Mobile USA are SIM locked to T-Mobile USA.  To be eligible to have the SIM lock removed, you must be a current T-Mobile customer and must meet all of the SIM Unlock Policy requirements to qualify to have  the SIM lock removed.  

SIM Unlock Policy | Unlock Your Mobile Wireless Device (t-mobile.com)