Shoppersstop.com — refund not received even after 3 months from returning the product

Website:

www.shoppersstop.com

I had purchased a kurti from shoppersstop app on 16th aug 2018 and soon returned it as it was not fitting me. After 1 month when requested for refund they tell me my bank account details are invalid hence they are unable to process my request, so i filled the google form once again and call their toll free number where customer care executive assures me i will get refund by 12th nov without fail. I was waiting for the amount to come then i receive a mail again today (22nd nov) that my account details are non-existent hence they are closing my case. I am shattered because after waiting for such a long time i get this response and on the other hand i do numerous transactions with the same bank account details. Please help.