Giant Union Co Inc

I bought a bag of roasted sesame seeds distributed by this company's Maru Kyro Division . It's over roasted, taste bad , and when I use blender to make sesame powder, I can feel that sand was mixed into the bag. The worst thing happened last night. When I use the blender to making sesame power, I heard strange cracking sound, so I stopped, put it aside. This morning , I checked the powder to see what's wrong with it, I found a piece of black coal !!!