Normally if someone wrote those words the most likely situation is your phone has an app / software update which hogging more cpu power. Wired charging is more powerful so you don’t notice it so much but wireless is weaker and so you notice it.
Look in your phone’s battery utilisation and convince yourself, eliminate, your phone’s software as the cause before anything else.
Next, the most common issue is either the phone or the pad just got confused. Fully power them off and leave them off a few minutes, power them on. In pad’s case that’s pull the cord out.
Next, the most common part to begin failing is the cable, small micro fractures slowly accumulate, the cable’s resistance increases. So try a new good cable.
Next, try different charger.
If, after, eliminating phone software, power off/on, cable, charger, it is still dud, it’s still most probably the phone which is at fault as the pads are very simple things, but if you want to, use your Anker warranty and email firstname.lastname@example.org with your order details, serial number, to prove you are the owner and in warranty, and they will offer up ideas I may not have thought of, or offer a replacement under warranty.
But, to repeat, this most likely an issue in the phone because it’s the most complex part of the end-to-end, so begin with that assumption until you’re convinced it’s not the phone’s bad day.