Family Dollar complaint: Poor customer service

There was only one register open an the line was wrap pass by where the soda is kept an you had 2 other employees stocking shelves and the other employee checking every body out by her self she had called serval times for back up but nobody came I stood in line almost 30 min . When the manager came she was on her cell phone talking on the Phone an not once when she got off the phone she didn’t apologize for everyone waiting in line .when it finally reach my time to check out I hand the employee the 50% off coupon for the 10 pack Bic Deuce the regal price was $3.25 so when she went to try to scan my 50% off coupon she said it doesn’t work I tried to tell her how to scan it because I used to work a family dollar as a manager an she didn’t listen to me so when she told the manager that was on duty she said it doesn’t work when she never tried to come over an find out why when you have a whole lot of these coupons on your product why have the coupon if the customers can’t even use them .