Revise these complaint letter (same topic and same ideas)only make it abiding complaint letter writing guidelines and  applying proper complaint letter format and content requirements, thanks for your help

Independent Practice: (revising a complaint letter) -- The following complaint letter does not abide by complaint letter writing guidelines. Rewrite it fully, applying proper complaint letter format and content requirements. Hi Man, It is very unfortunate that I had to write this letter to complain about rude behavior at your Bank. This kind of treatment is never expected from such a reputed Bank. I was at Beirut branch for a check withdrawal, then this one employee shouted at me. Whom does he think himself is???? I guess you and he are going to regret that rudeness if you do not take immediate action and apologize within 24 hours. I have been a customer at your bank since 10 years and have been satisfied. So, what has happened to you now?? I hope that such an incident was an accidental, and it will not repeat. No regards, Albert