A month ago I noticed my phone was only slow charging, and I was using the factory charger, the adaptive fast charger, I did some troubleshooting, and came to the conclusion my charger was getting funny. So replaced it. Now, no matter which one I use, the factory charger or the Anker +IQ, it still slow charged. Now on occasion it won't charge at all and takes unplugging and plugging it back in to have it charge. I've cleaned the ports several times but it doesn't seem to help much.
Maybe it's my phone itself with the issue?
Have you tested charging your phone with a known good charger from a store or from a friend with the same phone?
If your phone will quick charge with a known good charger then it would be an issue with your charger.
If your phone will not quick charge with a known good charger, then it could potentially be a bad charging port or a faulty battery.
If you are saying your phone will not charge at all, it may be a faulty charge port. Unfortunately getting these replaced at most repair shops is quite expensive.
Best of luck! be sure to post back with any update you may have.