My iPhone 6 stopped working completely. An Authorized service center in Moscow refused to repair or replace the phone because of scratches claiming that it felt down,but this was never the case. Any suggestions?

Did you consider to visit another Apple Authorized Service Provider? If they will come to the same conclusion, there is nothing you can do about that. Dropping the phone is not covered by the warranty.

What type of damages are not covered under my warranty?

Apple's Limited Warranty for iPhone excludes coverage for damage resulting from accident, disassembly, unauthorized service and unauthorized modifications. Please review the warranty for further details.

An iPhone that is ineligible for warranty service may be eligible for Out-of-Warranty (OOW) Service. For example, an iPhone that has failed due to damage or liquid damage is ineligible for warranty service but eligible for OOW service. However, certain damage is ineligible for OOW service, including catastrophic damage, such as the device separating into multiple pieces, and inoperability caused by unauthorized modifications. Please see Apple's Repair Terms And Conditions for further details. Refer to this article to check if the Liquid Contact indicator on your product has been triggered.

If your iPhone is not eligible for warranty service, you may wish to contact your carrier or an Apple Authorized Service Provider for other options.

Apple One-Year Limited Warranty benefits are in addition to rights provided by consumer law. Learn more.

copied from Service Answer Center - iPhone /Russia