Factory defective battery

My iPhone 5 had charging problem after 2 years of use. Consulted an apple service center and diagnosed to have failing battery and charging port problem and may need to be replaced for 16k! My battery is included in the free replacement due to factory defects. Unfortunately, it was not replaced because of Apple 2out of 4 conditions not satisfied! Why should that be? They gave a factory defective battery and that should be the primary reason to replace it, not to unrelated problem of the phone!

I use to put my phone in my front pants pocket when I go out. It never have been wet or dropped. But according to the service center, there's signs of moisture inside. That's the 3rd reason not satisfied! I believe it's unfair. And the issue is "still a FACTORY DEFECTIVE IPHONE 5 battery " so I brought my phone back home VERY DISAPPOINTED !

When I got home, I check on the charging port and I saw some whitish material in it. I tried to pick it out. And just to find out that the whitish material in the port was "cotton lint " probably from the pocket of my pants! Now it's CHARGING WELL! The service center did not see that!? I solved the charging port poor contact problem wo shelling out 16k! Still the issue is a FACTORY DEFECTIVE REPLACEABLE BATTERY! And Apple does not want to Replace It!!!!