H&m — NOn H&M item misplaced

Website:

www2.hm.com/en_in/index.html

My non-H&M item was wrongly picked by H&M, for which this brand only mistakenly raised a request. I agree it was our fault as well that someone wrongly handed over. But how come the agent picked up and why return request was mistakenly submitted by customer care? Also, after my complaint has been addressed with varied responses over the call- 1. the warehouse has not received any item OR 2. item has been reshipped 3. yes an item has been picked and bla bla. Why they are fooling their clients? I have clear proofs of their texts received on items picked up then why? How come if they have picked my item has not been received?