OK, this doesn't really give me any authority here but, hey, my brother owns a jewelry store. And I know he would advise you only to let a reputable local jewelry shop handle your ring, not a chain shop or "corporate jeweler" if that means a chain. You want a place that employs jewelers. Ask questions. Ask how long their jewelers have been doing that job, how much repair work they usually do in a given week or month, how they would propose not just tightening one baguette but how they would straighten that crooked main diamond, remove the bad solder and fix the setting piece that doesn't match the rest. Get an estimate. I'd get ALL the messy, shoddy work fixed, if it were me. It will cost you but if this is something you treasure you should be able to look at it and not cringe at all the problems a lousy jeweler created.
By the way, you want to find a jewelry store that has IN-HOUSE jewelers who will be doing this work right there on the premises--not sending it anywhere. Ask to meet the jeweler who will work on your ring -- don't just leave it with a salesperson, ask to see the jeweler too so you know this person really is on the premises. People who sell jewelry sometimes claim they are "jewelers" but that term really should only be used for people who are formally trained in the art of fabricating and repairing jewelry. I would wager that whoever messed with your ring was not trained or at least not well trained.
My brother sells jewelry and has trained in fabricating it, and is a certified gemologist, but he would never work himself on a ring like yours -- that is why he employs a full-time jeweler inside his shop.
I agree with the person who posted that you should let the Better Business Bureau know about the corporate jeweler. I also don't get the warranty thing unless you mean a warranty on the (terrible) workmanship and not on the ring itself. Be sure you have the ring insured through your homeowners insurance and/or a "jewelry rider" on that insurance if your agent thinks you need one, too!
