Waist trainer extender help

Does anybody know of a place I can get a waist trainer extender? I'd rather get one instead of returning or exchange it's a little tighter than snug I can put it on but it's uncomfortable and little harder to breathe tight. I just need it one hook loose. I cant find one on the website or on amazon with the correct dimensions of space between hooks/height. I Cant find a custom site that sells either. The brand is yianna. If anyone knows of a place I'd appreciate some feedback. Thx :)