I have an iPhone 6 16GB under warranty and due to some issues with phone I was in contact with the customer service team since 18-October-2017. The customer Service team tried their best to resolve over the phone but it did not help, thus helped me book an appointment with the Service Center ​(Unicorn Infosolutions Pvt LTD, Cyber Hub, Gurgaon​, India​) for repair.
​Case ID: 100325669049
Job Number: GGN2185751
On 29-Nov I submitted the phone to the Service Center and I was given a loaner phone.
I received a call from the Service Center on 4-Dec to advise my phone has been repaired and I visited the center to collect the phone on the same day.
The advisor took the loaner phone in the lab and came back to state that the loaner phone has a duplicate/third party display and they cannot give me my phone.

Now, this is where I need your help​ please​-
1. When they gave me the loaner phone on 29-Nov, they did not check the phone in front of me to validate the phone has genuine parts. Thus, I feel this is a scam run by the Service center engineers.
2. The phone had no sticker or seal to advise if the seal is broken the authenticity of the phone will be lost.
3. The loaner phone had a temper glass but the I guess Apple do not issue temper glass. When I asked the same question to the Service Center people, they advised previous customer might have done it.

There is a scam happening in the background and I am victim of this scam. At this juncture, I need some to help me please! I have lost all my trust from these people, thus contacting you for help.

I have been touch with Apple Customer Care to raise a complaint but till date there is not resolution. All I get to hear from Service Center is they are Apple authorized but that does not prove that I was given an authentic product and Service Center are not involved in a scam.