Family Dollar complaint: Rude manager

i went to the store @5:30 pm, and there was a sign on electronic stated 70% off and discount taken at the register, so i purchased a few and went to the cashier to pay for my orders, so i noticed they rung up at the regular prices, i told the cashier about the promotion, and she was very polite and called the manager named Jennifer, when Jennifer came in she looked at me up and down and told the employee that those items are not on sale and she is not going to override them either. i told her Jennifer (manager ) let me show you the sign, she went there with me and told me that she is not gong to do anything about it, when i asked for the store manager or the corporate number, she told me that she did not have them and i can google them myself. And also she was talking to other customers about me stated that she was going to call the cops if i kept on asking her for the number. THis is unsane i live in seaford and visit that store often , i will be taking my business somewhere else with that kind of management,