Default [Q] Disaster ensued after charging Samsung Note 2 with iPhone charger

It happened after I charged my Samsung Note 2 with iPhone (3GS) wall charger using the micro usb cable. First night, it charged so fast. Then from the next charges or two, it was very very slow. I moved back to my Samsung wall charger, but now it is still slow. I tried charging turning off, and it charged fast again the first time but not from the next. Now it charges super slow everywhere including when connected to a laptop. I measured current using Charging Current App, and it is about 300-500 ma. My suspect is either the cord or the battery. The wall charger is fine because it charges my note 10.1 well. One thing I noticed, the micro usb has only 4 pins. Shouldn't there be 5 pins? Is this the culprit then?