Swiggy — got a distorted cake delivery. swiggy not giving refund

I have taken a delivery service from swiggy for birthday cake of rs 500. The cake was totally distorted. I raised the complaint with the customer care. They were very rude and said we cannot do anything and can give you coupon code of rs 250. The cake is of no use to us. The customer care is also not giving us the contact details of its higher authority. I have tried to reach them in all the platforms telephone, facebook, twitter and mail but there is no help, just diplomatic answers. I want to sue swiggy. Their role is to make a proper deliver which they are not doing and then also not giving my money back.