Aurelia - Refund not received

I ordered a kurta from the website of Aurelia (https://shopforaurelia.com) and then I placed a return request for some reason.I recieved a mail from Aurelia(www.customercare@tcnsclothing.com) that I need to courier it to their warehouse. They asked me to share the challan receipt with them. I did so. I couriered it through speed post from Post office Chatra (******). I recieved a confirmation mail from Aurelia on *th July that my article has reached there and I'll get my refund within *-* days. They kept on saying this for about **-** days that I'll get my refund within a few days. But now after * month, they're saying that my article hasn't reached there and are asking for proof of delivery. But it's next to impossible to get the proof of delivery in this pandemic situation. Aslo in the beginning they didn't ask for it and confirmed that my article has reached there. Hence I didn't apply for pod while couriering it. They even confirmed it that my article has reached theri warehouse. Now they're not refunding me.