Osom in - Package not delivered

I'd placed an order for four T-shirts with osom.in on **/**/****. The order was confirmed via email, and the estimated delivery date was shown as between **/**/**** - **/**/****.
However, on the **th, the status was changed to shipped, but the tracking details showed that they'd not received the consignment from osom.in. I've tried reaching out to the e-commerce firm via email and phone calls, but they haven't responded yet.