Trendin.com — Refund not processed even after 3 week’s

I bought a t shirt from trend in.com(order ID 992276) .Since size was wrong I returned the item, return pickup was arranged by trend in.com and the item reached trendin warehouse on 26th January. I asked refund as trendin credit. If I send a mail, every time I’m getting a reply saying issue will be resolved in 2-3 business days. I have send mails 4-5 times and every time I was getting same reply.last week I called customer case and they assured solution within 1-2 working days but the issue is still not solved