Automatically was tipping 200 rupees everytime I ordered.

I just checked that I have been tipping 200 rupees everytime I ordered on blinkit. I am very sure I never added this tip amount in my orders. It just randomly started tipping 200 rupees. I realised this because the delivery guy called and thanked me for the tip. So far I have lost 1200 this way. I know I should have checked the bill and all but genuinely this is the worst app experience. How did it randomly just start tipping 200 rupees without my knowledge??