I would suspect a fault with the phone, rather than battery or charger.
Although the phone is indicating a rapid loss of charge, is this indication correct? If you continue to use the phone, does it switch off due to a flat battery? With such a rapid discharge, the battery should become quite warm to the touch.
If you can access another Galaxy Note, after charging the battery in your phone – transfer it to the other phone and see if it discharges quickly. Also place the battery from the other phone in your phone and see if it discharges quickly.
With access to a second Galaxy Note, there are a number of tests you can conduct that would assist in narrowing the fault – you just need to use a bit of logic.