H&M Western (INDIA) Private Limited - Months Have Past Refund Not Received

They delivered the wrong item (*rd April, ****). When I called the delivery man, he informed me that I ought to schedule a return seperately. Immediately on the same day, I scheduled a return. They collected the items from me on *th April, ****). I have the mail from them confirming so. Then despite multiple calls, despicably long call waiting, and rude behaviour with their agent: I received a mail on **th April, informing me that they items have reached the warehouse and the refund is under process. However I received no refund and no communication whatsoever from their side. And all my calls to them enquiring about the status - all in vain - cause they always made excuses. Today they informed me over call - where in I was the one calling them up again - that my return had never been received in the warehouse. And they cannot do anything: it's **th July today, i.e. * months since their big botch up.
This is entirely unprofessional: moreover: their lack of communication and concern was even further aggravated by their misdemeanor and rude behaviour.
THIS IS NOT OKAY!