Of the things I've sent to them, my one problem was regarding 2 bracelets - one of which broke again immediately that I wore it (it had only broken the once in 10 years which was why I sent it to be mended), and the other was with some charms/pendants they put on for me and neglected to remove the bale from one of them so it looks awful.
Other than that I can't comment. Sorry to hear about the situation Meggie. I trust they will refund your money and carry out the work free of charge for such a glaring error.