Louis Stitch Shoes - Bad products shoes delivered seller not responding to return refund request

I had ordered * pairs of Louis Stitch shoes online (through their Instagram account) on **-July-**. I received my order on **-July-**. However, upon trying the shoes I noticed that the sizes we all wrong - i.e. I had ordered my regular size UK*, but these shoes felt at least * sizes smaller. Same problem across all * pairs. Hence, on the same day I wrote to their customer service (customerdelight@louisstitch.com) asking to return all the pairs and a refund of my money. Initially they offered a larger size, but I declined the same. On **-July-**, they accepted my return/refund request and asked me to fill the details with pictures on a link provided in their email, which I duly completed. Since **-July-**, the shoes are still not picked up, and there is no response from the company on email or whatsapp. I have received multiple SMS from their shipping vendor for pick up, but no one turns up. Whatsapp messages are being ignored and answered by a marketing bot.

I would like to return these shoes at the earliest and claim my refund please.