Flipkart joke customer care services

I have a fashion product coupon in FK. I have ordered and due to a few concerns I cancelled. Now the coupon is expired. I have asked cc about the same and they are saying u can only use once. Lol, that cc doesn’t even know the T&Cs and randomly saying the same. I asked her that on what basis she is saying that coupons can be considered as used even for cancelled products. She quoted one of TCs which is referring whole other point. LMAO.
Still frustrating

It isn’t about coupon, it is about these CCs fooling customer.
Any suggestions how should I proceed with them?