Walgreens Congestion and flu medicine

Neibours,

I caught the flu and baught a bunch of Walgreens congestion, flu medicines that also targeted pain and they do not work. It was a horrible experience knowing I had just taken acetaminophen but still in so much pain and unable to take anymore meds for fear of overdosing. How are pharmaceuticals allowed to sell drugs that do not work? Has anyone had this same issue?