Paytm Mall - Return order not picked and money not refunded

I purchased a Liberty shoe on the **th of November from Paytm Mall. The size went a bit big for me so I placed a return request on the same day of its receipt i.e. on the *th of Dec ****. Even after the passing of ** days no one has come to pick the material and neither the money refunded. The shoe was purchased for **** with cash back of ***, so the effective price was Rs ****. Tried to contact customer care but every time it was routed to mail for which they are not providing any response till date. Such a big company with such practice is unthinkable. I would like my money refunded and material taken back as **** is not a small amount.