Necklace bought from ZANDO damaged!

A week ago I purchased a necklace from Zando which was on express delivery and paid for via credit card, on inspection of the necklace less than an hour after delivery I noticed that a stone was missing, I immediately called the helpline were I was advised to login to my profile and request the necklace be returned which I then did..(problem was I wanted the same necklace) so I was told to reorder which did not seem right to me as it meant I would then have to pay again for the necklace and delivery? I called back and spoke to a very helpful Natalie who explained to me that I had been advised incorrectly and that the reorder should have been done by them so that I would not have to repay and that I should take a picture of the defective part and email it to them so that the process would go through faster, the damaged necklace has been returned but I have not received the replacement necklace and I NEED it as it was purchased to wear at a wedding this weekend. Extremely disappointed and feel cheated by Zando, will not be using this site for purchases again and I advise others to steer clear rather buy the old fashioned way by going into a store.