Review on City Threads Sensitive Friendly Clothing Boys' Clothing ~ Underwear by Corey Krull

I used to buy Hanna Andersson underwear for my children. I tried City Threads because the price for 100% organic cotton underwear was great. However, it was another lesson in "you get what you pay for". The stitching started to unravel after a few months (see photo). We've tried almost every lingerie brand over the years and I've never seen a pair of City Threads unravel like this before. How difficult is it to sew the remaining seams?