Former Liverpool and Manchester City midfielder Dietmar Hamann has quit as manager of English non-league club Stockport after just over four months in the job.Hamann, capped 59 times by Germany during his playing career, undertook his first management assignment at Edgeley Park this summer following County's relegation from the Football League.His appointment to replace Ray Mathias coincided with the promise of new investment in the club from Liverpool-based businessman Tony Evans.However, a deal failed to materialise and after three league wins in 19 attempts, Hamman cited the collapse of Evans' takeover as the reason behind his decision to leave."Following a meeting this morning between (chairman) Lord Snape and myself, I have tendered my resignation as manager of Stockport County," said Hamann."Having been introduced to the club by Tony Evans, I presumed that the takeover by him and his consortium would have taken place."Various promises were made to me at the time of my appointment which subsequently did not take place. I feel therefore unable to continue in the post."