Swiggy Instamart — Delivery issue

I ordered 9- 10 items from Swiggy Instamart. None of the items mentioned on the list got delivered. Instead some other 4 items have been delivered.
This is highly disappointing and irresponsible. I have been a customer of swiggy for so long and it is not something expected from Swiggy.
I need a refund as soon as possible. Had a chat with the customer support but it was of no help.
Hope this issue gets resolved soon!