Ecom Express — Return pickup collected and not updated the status

Hello,
I have ajio return pick up schedul and ajio doesn't share AWB or tracking no. The delivery agent collected the parcel and he didn't update the status and the item didn't reached ajio. Soy refund didn't processed. This is the second time in facing the similar issue. Previously I faced issue with Myntra pickup where i ended up paying from My account and delivery guy updated Myntra saying they didn't collect the parcel. For acknowledgement both the time they said the.process changed and now they are not giving acknowledgement. This time his picture and mobile no captured by apartment entry application but the no given is wrong no. Seems like Ecom express delivery agents stealing the return pickup items and i see there are many complaints. Now to whom I have to contact