Fed up with contentiously bad service!!!

I'm visiting this store at least once a week and wanted to file a complaint so many times before but with the event that happened on Friday i can no longer keep quit. I was standing in the line for more then 15min waiting to pay for my goods their where only 1 cashier handling sales, telephone & new accounts, the line was 3 people before me & about 4 behind me the whole time i was looking around to see where the other staff members are and wondering why they can't come and help this lady. Eventually when i get to the front i ask the lady why is she the only one serving customers you can see the frustration in her face and she ask me to talk to the manager(who was standing at the entrance of the store hanging over a clothing rail talking and laughing with other staff members. When I ask her why is everyone just standing around and their is only 1 cashier handling everything, then the manager told me she is merchandising, i ask her what is she merchandising because she was just standing their the whole time while I was in the line. Then she started to laugh me out, I told her that I'm going to file a complaint then she told me I can do just that. I'ts unbelievable & terrible service