Diamond z4 wedding set

I order the rings and after some time I finally received them. But after having wearing them for like 3 day they started to turn my finger green,not cool!!!! And now one of the jewels have falling out! I would like to return them not for the money back but for a different set,one that is sterling silver and that none of the jewels fall out!!!! Not plated but real silver would be nice,since that is going to be my wedding set for when I get married in April of 2013. I would mean a great deal to me. I love the rings they are very beautiful but not when turning my finger green!!!