I have worn these twice and the second time I noticed the stitching in the left inside was ripping. It has been a hassle trying to take them back to the store because I live 2 hours away. So I am hoping that I may be able to just fix it myself.
I do a lot of my own repair. However, this is one where I instead work on the idea of 'consumer relations'
My attack: Phone the company that made them. Explain the problem, and ask how to get them replaced. (You can email them but this will add 3 days to the exchange)
For this to show up this soon, either the sewing machine is out of kilter, and the stitches aren't locked -- and ALL the stitching made on that machine is faulty. Or the thread is faulty, and the whole boot will be parts soon.
Many companies will respond to a well written complaint like this: They can't afford bad reviews.
What has probably happened is that the thread used on the boots has deteriorated. I would hand sew it, but only after studying the best knots to employ in the repair. Be sure to use the same holes made by the machine in order to avoid weakening the leather. Once finished, spray with a water repellent compound.
I have done this on my own shoes and have had some success at it!
PS: Chose your thread and needles carefully.