Concert Ready Jeans - Rhinestone Jeans - Brand new!

I just received today and unfortunately they don’t fit. I’m between a 8-10 and I have big hips and with the no stretch, my behind is just a little to big. (The medium is for 7-9) If the strings do unattach you can reattach, jeans are delicate from what I read on reviews but I was able to try on and remove with no problem. Photos attached!