According to the announcement by Apple, these iPhone 6s and iPhone 6S Plus might not be able to be powered on due to a faulty component. Identifiable through their serial number, these devices were apparently manufactured between October 2018 to August 2019.
In order to check whether your unit is affected by the issue or otherwise, all you need to do is visit this site and enter the serial number of your phone. In the same announcement, Apple has also noted that customers can reach out to the company and request for refund if they have paid to rectify the no power issue on their devices. However, the free repair program will not extend the warranty of their devices. For further information, just head on to Apple Malaysia’s website. (Source: Apple Malaysia.)