Lacoste not providing any refunds after taking back products

I am very disappointed in Lacoste's online services. I ordered a product in December and immediately sent it back as it did not fit properly. I did not receive any communication from their side for a month and when they finally contacted me, I was promised an in-store voucher. Now, almost a month later I have not received any voucher/refund. I believe that I hace been ****med.