Ajio - Package not picked and money not returned

I ordered Nike shoe from Ajio. Due to the size issue, I raised an exchange request. But the logistics team didn't exchange the product and return it to the vendor. On May **th **** they informed me the vendor received the product and by May **th they will pick the product from my home and return the money for the same.
But from that day whenever I call to their call centre they ask me to keep patient for * business days but never give me the solution. I also talked to their supervisor Mr Praveen from Bangluru. He also asks for * business day time twice but it was a false commitment again.
I called them on May **th, **th, **nd, **rd, **th, **th, **th and also today(**/**/**). But found no improvement.
They gave me the following complaint no.
*. COM***********(**/**/****)
*. COM***********(**/**/****)
*. COM***********(**/**/****)
*. COM***********(**/**/****)
*. COM***********(**/**/****)