Customized name necklace

Hi. In Nov 2015 I have bought a customized necklace. Before going on Holiday I have noticed the silver changing. Went on leave and silver turned blackish. I contacted Netflorist in Jan and the gave me advise which I followed, but did not help. The then advised that the will come and collect, 3 weeks and still have not picked up the necklace. Every time I mail the the say tomorrow. <br> Please can you assist