Little big story, but do not have a solution yet
I bought a 16GB 6S in August 2016. The phone was very good and no issues until August 2017. We went for a trip to ooty in August 2017 and it was raining heavily, the phone did not even get wet because it was inside a bag. But that was the first time I noticed a "No Service" issue, thought it might be due to climatic conditions, hence kept the phone aside and it started working the next day morning once the climate was back to normal.
This "No Service" was happening on and off and went to check with the Apple Authorized SC in Chennai (@ 12th Main Road, Annanagar) in September 2017, they checked for 10 minutes, came back and said replacement is the only option without mentioning what the issue is. I was persistent on finding the issue, but they never gave me an answer and were least interested to talk too.
So went to another authorized sc (Chintamani, Annanagar) and they asked me to first check with my sim and asked me to get the 128 bit sim (some are 64 bit), since they wanted to rule out that cause. I did that, but still the same issue and they did a reset and did a diagnostics for couple of hours and came back saying that there are no issues in the phone and use it as far as it goes.
During all these months from September to April, sometimes it worked, sometimes it did not. When I went to the service center both the times, it was not working. Then I left the phone idle for some days, suddenly it would pick up signal and start working by itself.
From April 2018, the "No Service" issue was not going off like before. So called Apple care and checked with them. They asked me to do a reset by connecting to itunes, did all that they mentioned, but still it was not working. So they suggest to go to an Apple Service Center (ASC), went to one and they were the worst of all the SC (@Inorbit mall, whitefield) I had visited. They just heard the issue and told replacement is the only option, without even doing any diagnostics. I mentioned this scenario to Apple customer care executive and that person also accepted that this is unacceptable and they will raise a complaint internally and take action. They asked me to go to another SC and they asked for options and I mentioned that HSR layout is the nearest one and they booked an appointment there.
Went by around 6.30PM to HSR ASC and they said your case ID has already been passed to us and we will do the needful. I asked them of what they will be doing and they said it will be diagnostics and after asking what kind of diagnostics, they said software. I was tired of explaining same statement again and again, so for one more time I explained that there is no problem with software and all the reset steps were already carried out and its something else with hardware. But they did not listen to me and insisted that they will do only software, phew.
Made a call immediately to Apple care and did a conference call with all 3 of us in the same call from the service center itself and the service center person accepted that he will do the hardware diagnostics, but since it was already 8PM (yes, I was there for nearly 2 hours), since the store is closed by 7PM, the SC person asked me to bring the phone next day morning, which I promptly did.
Another twist here is that he totally forgot (or acting so) and asked what the issue was, later explained and he said Ok, I will do it but I had to bare the diagnostics expenses which is Rs. 1178/- since the phone is not under warranty for which I said, I am ok to pay, but please find what the problem is, but don't do the software diagnostics again and ask for the money, he did not listen to my points at all. I even mentioned that I am ready to pay for the hardware if you find that is the problem, because its better to repair the phone than to get a new one. After 2 hours, I get a mail saying that its beyond repair (attached document is their mail), no reasons of why its not working or what the exact problem is.
Post this, I asked what options do I have and they mentioned replacement. Ok, for replacement the options are either get a replacement phone with same specification for Rs.27000/- with only 90 days warranty or upgrade to a new phone and they will take this phone for Rs.4000/- with a 1 year warranty. What's the reason for a 90 day warranty, because that is a refurbished phone and they said that after I asked for it.
After all this, I again called the Apple care and since I created lots of issues in 1 week, my case was transferred to a new person who claimed to be the Senior Advisor and any communication further will be with that person on this case. I explained all that happened and asked how can a premium company like yours not find what the issue is. After talking for 5 minutes with no proper answer from them (which I was expecting), asked what is the solution and that person also said replacement is the only solution. I asked how can you people be so dumb, when you cannot find what the issue is, what is the use of having a service center. Blackening of screen - is this a reason for "No Signal" issue. I was totally upset and had to hang the call since I knew that I was wasting my time and energy talking to them.
I am not interested to go to local mobile shops to fix this issue, not sure if they can fix it too. I also work in a product based company but never had come across such a product or service support.
Someone might ask on how I did not go for an extended warranty, actually I was not aware until I talked to the Apple care person that there is an extended warranty for phone's too, I am not much tech savvy, but post this harrowing experience, I am becoming one.
So, it is pretty clear that they are looting people. They know what that issue is, which is clearly something related to hardware. Get this phone for Rs.4000/- , change the motherboard (worst case) and sell it again as a replacement phone, so a profit of approximately Rs.13000/- (27000-4000-10000{mother board})
I had made a complaint in consumercomplaints.in and Jagograha, but yet to get any response.
The phone is idle now and no solutions even after I tweeted them for answers and I might have to use that as an Ipod after this.