Paytm — no proper refund and no customer care

Hello. I have ordered for a case for oneplus 3t on paytm mall for rs. 263 and paid through debit card and received rs.100 cashback. Cool but the product i received was completely different from the one i ordered and it was damaged. So i requested for refund they accepted and picked the product back. On my order page it was written refund of rs. 153 was processed on 08 sep 2018 and the refund would reflect in my account within 14 working days. Today is oct 23 still i haven't received any money. When i called their customer care it's being on hold for hours. When i try to email them it's not delivering. So who do we approach? Is this a new way to loot people's money?

This is not about money but about trust. What if i ordered a product worth of rs.15000 and faced the same issue?

Here i've attached the photos of what i ordered and what i received. Thank you