XL underwear is way bigger than AU and jokey underwear exactly the same size

I thought to buy underwear for my husband for the first time at Eagle. We wanted to buy Jockey originally. We should have!!!! Brought yesterday from 2 very nice Ladies at Welkom Eagle clothing branch with friendly and helpful service. But this morning my husband took out the underwear wanting to wear it. He said it looks way tooo big!!! It’s XL and we always buy XL that fits perfectly when we buy Jockey/AU brand. I wish I can post a pick with the size difference for these. Anyway we still kept the bag and proof of payment and the underwear has not been put on at all. Just taken out of the package. When we took it back they refused to give a smaller size. Apparently if we have opened it inside the store they would swop it…. Does not make sense at all!! You can clearly see it has not been worn. So what now? Do I just throw the packet in the dustbin? I’m not buying from Eagle again. I will just stick with what we know works. Very very very disappointed.