When my mom have problems with her 2nd-hand S4 that still have 3 months warranty, I tool it down to their Service Center in town. After a short wait, I was finally served by a officer. The officer said that they could not solve my problem because the phone has been tempted before. I asked for more details because we were told the phone is still under warranty and that we should have no problem.
She just repeated rudely that the phone is tempted and they couldn't do anything about it! I told them I was cheated by the reseller and asked her if she could provide me with some evidence or a statement to prove that so that I could go back to the reseller with it.
What she did next is totally unacceptable - she just ignored me and then turn to call the next customer in line! So I told her this is not acceptable and I wasn't done asking.
She glared at me and then asked for help from her colleague beside and I was called over. He asked me rudely, "what is wrong?". I told him the situation and he said they could not show me the evidences unless their manager approved it. So I asked for the manager and he just said, "our manager won't be in the whole day, you should come back another day!" And he went to call the next customer!
This is the kind of customer service they provide! In the end, problem was not solved.
Luckily, our reseller was kind enough to check for us and then exchange a brand new phone for us as apology.