What is the best way to handle a case of false advertisement?

when the advertistment is in writing





example:advertistment says





Join our discount club for $$ a month and recive $$ percent off our online store is open with customer service 24/7





(but every time I go online in the evening they there is no one to assist me. And they say it's because of my time zone does this make any sense 24/7 is 24/7 no matter where in the world you live right?What is the best way to handle a case of false advertisement?
right better business bureau

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