If the reason for the return of the product is genuine (damaged product, or a persistent issue), I would recommend the following approaches (this might as well apply to other brands) ...
Reach out to the customer support e-mail and mail them the issue along with a detailed description of the issue, along with photos of the defect (if the problem is visible).
Alternatively, you may have also have the option to fill in your grievance in the website form.
If the brand or the company has support ids on social media (most notably Twitter and Facebook), Tweet or update the issue. Most companies assign priority to cases that have been posted to their support handles on social media. (I was heading digital for a well known brand, and I have first hand experience of this).
If responses aren't forthcoming or to your satisfaction, find out email ids of key personnel who work for the brand(clue: Linkedin and Google are very resourceful in getting those ids) and send a strong message.
If all the above fails and you have beaten your head against a wall to get your return processed, go ballistic and post the grievance verbatim to complaints and reviews websites like Mouthshut, Akosha and the several websites that serve such a purpose. This will get their attention, and also serve a warning to potential customers about their lack of responsiveness (2 birds with 1 stone).