exaggerated power rating

I invite this unit my Galaxy Tap.
If the Galaxy device is turned on and it is running as a video, and Mumbi charger is used,
there will be no charge on the batteries, but a drain on the battery as opposed to the original charger.

Even otherwise, the charge of the Samsung Galaxy Tabs takes compared to the charge with the original charger (2 Amp)
about three times as long.
Had the postage costs compared to erwartenen refund
not so high, I would give the best part back.
I have not measured the output power, but the promised 2.1 amperes
brings this charger certainly not, probably 0.75 amperes.
And for that, I have not bought it. Such weak chargers I have namely already.