unfair and *********

A few weeks ago i bought underwear from mr price. The package had been opened and without my knowledge two smaller sized underwear was squeezed in amongst the medium pair i bough. At that time they where the only mediums in the style i liked so i thought what the hell and bought them. My husband has just returned home with more underwear that does not fit. The package has been opened and i understand there are rules ect...my question is that i have seen open packages of underwear on their shelves a number of times and have fallen for the trick of buying for them which is my .own stupidity but i seriously feel cheated. The response i got when i called and said the underwear was untouched and can i bring it back was shocking. The lady who answered was extremely rude and brushed me off completely. Not to mention this underwear was bought less then an hour ago. I am very sad yet again to sit with clothing i cannot wear and just deal with the loss of money over and over again. Like i said i understand the rules however the way i was spoken to and not even heard was un acceptable not to mention the feeling of being cheated because this mr price sells underwear stickytaped and opened any