Mouldy Chocolate

Yesterday 29.02.16 I purchased a 80g slab Mint Crisp chocolate. The expiry date on the chocolate is 21.04.16. When I opened the chocolate it looked mouldy. I tasted a piece and the chocolate doesn't even melt in my mouth the way a normal chocolate should taste and taste mouldy as well. I would like to know why products like this could be sold to customers. I have not been feeling well since eating this chocolate. I would like to get some feedback regarding this matter and I have kept the chocolate as proof.<br>