I just received my Boden O6 and after playing for 20 minutes I noticed the high E was going out of tune...So I re-tuned it and it continued to do the same. On the 3rd attempt of re-tuning I heard a ping, and I now the ball end of the string is sticking out of the back of the tuner. I have loosened the locking nut and pulled the string through further, which has in turn pulled the ball end of the string back into the tuner. However, I can not get it to pitch (E) it just keeps slipping out of tune. This is my first Boden, I could be doing something wrong, but I don't think I am. Standard tuning. All other strings are fine.