Zepto's new ways of tricking you in paying more money

Today I ordered from Zepto and the total bill amount was 315 Rs. I was carefree about the delivery charge as I have availed Zepto pass. To my surprise I was still charged with delivery fee of Rs. 30 despite my order value being greater then the threshold. Tunrs out you need to manually click on a " Apply Coupon" button every time, when you order, to get free delivery. And that too I have to expand a separate section where the billing details are written and obviously the "Apply Coupon" option is smartly hidden in that section. Be cautious while ordering or avoid Zepto completely.