Poor customer service

On the 03 June 2021 I bought leggings at Game gateway and it was the wolromg size, today I went in to exchange it at Game Galleria they told me that I can't exchange leggings my question was why they is no sign that says we can't exchange leggings even at they customer service department they is no sign the ladies that were there they were busy saying usually they is a sign being them. But they don't know who took it , now how was I suppose to know that I can't exchange leggings if they is no Big sign in the department visible for anyone who buying to see ? Even they lady that was working in that department she kept on saying she is not sure