If you have a problem with your smartphone (Android or iPhone) that you need help with then I'm the guy you're looking for.
it's a software problem I can guide you through the process to fix your
smartphone, if it's a hardware problem then I can recommend you how to
deal with it in details yourself or gives you tips how to describe your
problem to a phone technician so you can avoid his "extra-charge".
I will let you know the risks of having your warranty invalidated first hand(ADVANCED PROBLEMS LIKE CHANGING A BROKEN SCREEN)