No, we do not do such a thing. If a price goes down, you may purchase it in that time of offer.
If you find a ring is not a perfect fit for your finger, you can return it to the company's address given on the website. However, we would appreciate it if you checked your size before making any purchase.
There is no issue you will face in most cases while making any purchase. Still, if you find it hard to proceed with an item, you can ask for the customer support given on the website.