Bbdaily subscription coupons (existing customers) worth Rs.300/600/900, can possibly be combined with ICICI Rs.100 cashback over weekend

I just got a notification for this offer: https://www.bbdaily.com/fre...ml

For Existing Customers:
bq. 1. Get up to Rs300 worth subscription coupon free on recharge of Rs1000. Coupon code – diwali1000. On any one item Potato, Tomato, Curd/Dahi, Bread, Eggs, Banana, Tender Coconut, Paneer, Buttermilk. Total 6 free delivered (1 free delivery for every 4th paid delivery)

2. Get up to Rs600 worth subscription coupon free on recharge of Rs2000. Coupon code – diwali2000. On any two items Potato, Tomato, Curd/Dahi, Bread, Eggs, Banana, Tender Coconut, Paneer, Buttermilk. Total 6 free delivered (1 free delivery for every 4th paid delivery)

3. Get up to Rs900 worth subscription coupon free on recharge of Rs 3000. Coupon code – diwali3000. On any three items Potato, Tomato, Curd/Dahi, Bread, Eggs, Banana, Tender Coconut, Paneer, Buttermilk. Total 6 free delivered (1 free delivery for every 4th paid delivery)

There is also an ICICI cashback offer of Rs.100 for recharging at least Rs.2000 using netbanking over the weekends, so these two can be combined.

However, I am not sure how the subscription coupons work and what the terms really mean. Is this like a wallet balance that can be used to pay for any subscriptions? What about existing subscriptions like milk? Can anyone throw more light?