several shipments of the same Article

I do not understand. I ordered these two briefs fullsize and each time they send me midi sizes. I just returned yesterday with the second package noon, with the corresponding coupons, and today I still get the same product. I can not use twice the same return coupons but I prefer to cancel this article to receive three consecutive times, or the size does not suit me. So I expect to return other coupons which still has just arrived today.
Thank you for your understanding.