possibly British dark rap song

rap/hip hop song that has a very dark sound to it and is fairly slow. the rapper is almost muttering the words in a British/African accent. I believed the lyrics included bits such as "you're a goddamn liar" (this is repeated a few times) and something about "turn off the lights" "mandem" is mentioned a few times as well. If it helps I heard it in an Urban Outfitters via /r/NameThatSong http://ift.tt/2surX5R