British R+B star MARK 'THE MACK' MORRISON has hit out at critics who write off his troubled career, boasting his huge record sales speak volumes. The RETURN OF THE MACK hitmaker has enjoyed more trans-Atlantic success than pop superstar Robbie Williams, despite writing many of his tracks from behind bars in a London prison. But despite his impressive resume, Morrison is upset he still struggles to find endorsement from the music industry. He says, "We did two million records in America. And a lot of them were done from a jail called Wormwood Scrubs. It's just a blessing to me. "I'm aware that I sold more records in the States than Robbie Williams, and Robbie Williams is a great pop artist. "Leave it at the facts. I sold two million records in America. Yet the biggest artists from over here can't do that. "Still, a major label doesn't want to give me a chance to redeem myself. Why? Because I went to jail? Because I didn't want to do my community hours? What did I really do?" Morrison was jailed for one year after violating a community service order issued for his involvement in a nightclub brawl in 1995.