I don't think you will have any problem exchanging it for a new one. I am a long time Tiffany silver customer and I think that they are very eager to accommodate clients. It's sad that it happened to you on your very first purchase. It would have been better if it had happened to someone like me, as I have a regular SA and I have confidence in her and the brand. I really hope things go well for you with this.
Dear Diane, you are so kind, am touched by your words..