Swiggy — Number of cakes delivered less than ordered and paid for

I ordered four cakes from Parfait Cakes N Bakes at Balfour Road, Kilpauk, Chennai on Dec 28, 2021. I ordered through Swiggy. Of the four cakes, two were the same kind. I received only three cakes, one of each. When I pointed out this to the delivery guy he told me he was given only three and I should take it up with Swiggy. I immediately filed a complaint with Swiggy. However, I got response for two days. When I contacted them again, the chat bot informed me that they could not verify my claim and that they cannot process a refund and that the matter is closed. But the order update invoice clearly states delivered three items. Since I paid for four cakes but received only three, I believe I am entitled to a refund on one cake.