Samsung — Tab battery draining very fast

I visited 3 times to the service centre for the same issue...(my tab battery is draining so fast).Everytime they makes excuses and return back the tab.

Once they registered the service request ([protected])and then on the very next day handed over my tab by saying it's good to go...
But when i used that for a single day..same problem...i again visited the centre and again they rejected to check for any hardware error...
Even they don't have manners how to treat an costumer at all...

Address of service centre:-

Samsung Service Center
[protected]
https://maps.app.goo.gl/HwPfxhE9hCYMHYGk7

In just 4 mins battery drops from 6% to 0%