Didn't get my delivery and there's no respond all of a sudden

First of all I paid for the necklace and they gave me a date when I will receive my package, on the last day they changed the date with another week, did that twice. Long story short I never got my package and can't get hold of them, being sending 100's of mails and no respond. Best of all is was a Christmas gift and end of the day had to go and buy something on the last minute!! Wasn't special @ all!