I've been using a muller U3 choke for around a year and have been really impressed with it until I came to loosen it off after a round of sporting this morning. I tried to turn it loose by hand but it was really tight which was strange as it's always hand tightened I then noticed a crack in the extended section that you could see daylight through. Upon removing the choke the split ran the full length of the choke. Has anyone had any dealings with Muller, what's there customer service like I don'