Blinkit — Deducting tip from customer without their consent or information

Address:	Gurugram
Website:	Blinkit

I ordered some products today from blinkit and they added Rs, 100 as a tip in by bill during checkout without asking me.
When i complained to customer service they said they can not do anything about it,
Even if you order Rs100 order they are charging 100 as tip apart from night charge delivery charge etc.
100 rs, over and above all of this. This is unacceptable. Their is no option of checkout, Now they are not refunding my money