How can I ask apple give back my old phone

Dears,

I am writing for help that HK apple replaced my phone without any notice, which is commemorative with my favourite star signature.

As my phone display screen was broken on 15th April 2016 and make a reservation to talk with apple care staff online. Apple care staff has contact me on 16th April 2016 for assisting, I have mention to her that my phone is commemorative and look forward to repair the display only. She try to make a booking for me to go to TST apple store but the schedule is not updated so cannot be make booking. She advice me bring the phone to authorized service provide (repair center) to repair.

So I have make repair booking on 19th April 2016 to repair center and told to them I also mentioned I will only hope to repair the screen and will not consider the replaced the phone. The staff told me if need replace the phone, apple will notice me for decision. Also, if I need to replace phone there are extra charge. I also have show the staff that there is a signature on the phone and mention my request is repair display only. The staff explains if the display cannot repair they will send back the phone and i agree. So I only pay the display repair charge and service charge.

But, on 26th April 2016, I received the call form repair center me to collect phone and told me that apple have replaced my phone but no need extra charge. I was so shock and ask my request is only repair the display, then let the staff the check again but he say as apple record, they also didn't receive notification form apple, just said my phone have been replaced. I asking for the reason but he said this is apple decision so advise me to call to apple.

I have all the apple care and they transfer my case to senior department for help. The first staff i talk with is she told me my phone serial number is still available and show the phone should be in repair center. And she also said the case is so strange that replace my phone without charge. And the senior staff let go the repair center and let them have conversation directly. After their communication, Apple Care staff tells me repair center also set up a case with apple to call back the phone.

As I was so shock and depress on this case, i even cannot go to work on next day. On the same day afternoon around 4pm, I received call that apple is rejected to give back my phone. I was went to pieces that I have mention for so many time that how commemorative and important to me. But I cannot get back my phone and they told me cannot tell me the reason. I call to apple care again but the male staff is only told me even he is the most senior department but they cannot help me anymore. And the didn't know any contact of repair department.

I just want to get back my phone. Please help. Please tell me anyway can found the repair department.