iPhone 6 Unable to power on after battery replacement

On 31st Jan 2018, sent my iPhone 6 to Apple Authorized Service Center (QCD@Sunway, Malaysia) for a diagnosis and battery replacement as I was experiencing severe battery drain. A diagnosis tests was carried out by "Apple Certified Technician" and no issues were detected but technician suggested to proceed with battery replacement considering that the device was more than 3 years old and the battery might have worn-out.

Got the phone back on the same day, checked its basic functionality and everything seemed normal. Took it home and used for another day without additional app installed in order to monitor the battery consumption.

On 2nd Feb 2018, woke up in the morning and noticed the phone wasn't responding (battery was at 40% when I went to bed). Tried charging the device for a while and performed a hard reset (Home + Power Button) but nothing worked.

Reached out to Apple Support, tried troubleshooting the iPhone 6 few more times as advised by the Support Advisor, nothing worked and he concluded that the device should be sent back to Service Center for further diagnosis.

Brought the device to same service center and told the technician something is wrong cause the device wouldn't turn on or charge. She then connected the iPhone to a diagnostic device and said the battery looks fine but suspect the logic board might be faulty. At this point I knew I'm completely screwed !!

She then advised to contact Apple Support to take it up with them cause the Service Center would not take responsibility for any faults that occurs after the device collected by the customer in working condition post battery replacement.

At this point my nightmare started and I kinda knew this may not end too well.

Contacted Apple Support

1. First agent's response, said he would get a technical specialist to evaluate the issue and he transferred the case to another agent.
2. Second agent's response, said the logic board might already been failing and coincidentally it died after the battery replacement and there's nothing else he could do cause the device is already more than 3 years old and its out of warranty. He transferred the case to another agent.
3. Third agent's response, said he would try to check with the service center what happened and see what else can be done. Few hours later called back saying the device is dead, the device is already more than 3 years old and its out of warranty and the only way forward was to pay for a replacement unit. Told him it's not an acceptable solution and I want the case to be escalated to their next level support.
4. Fourth agent's response, said she would try to check with the service center again on what happened and see what Apple could do. Called back a day later, said the device is more than 3 years old and its out of warranty and the only way forward was to pay for a replacement unit or Apple would issue a e-voucher amounting to the value of battery replacement cost for purchase of new Apple product limited accessories only. Told her that is not an option and I need to know what went wrong and why the iPhone died all of sudden and how can Apple fix it. The phone was sent to a Apple Authorized Service Center and replaced with Apple Certified replacement part so something must have gone wrong elsewhere and Apple should do something to fix it. She said apologized and offered to escalate to their technical specialist for further investigation and told me to call her back if I changed my mind and willing to take up Apple's e-voucher offer.
5. Case escalated to technical specialist for further investigation........

Searched Apple Community to see if anyone else faced similar issue, none found hence decided to share this here for others reference.

Apple doesn't have their own service centers in Malaysia hence it's outsourced to other companies as Apple Authorized Service Center.

Been using Apple devices since 2008 and always admired its commitment for producing good consumer products but after so many years I too have been shortchanged by Apple Support simply because "I choose to send my iPhone 6 to Apple Authorized Service Center to replace with Apple Certified Parts by Apple Certified Technician!!" and "I was using a 3 year old product that's out of warranty!!"