Myntra.com — return option not visible for recently purchased item

Website: Myntra

I recently placed an order with multiple items in it. I want to return one of the items in my order. I see that it is out of stock at the moment, and i cannot see the return button in my order list. Only the exchange button is visible but even when i click on it, it shows a button to return item but it isn't functioning. I cannot exchange it as well since all the sizes for the item are out of stock.