Fail to honour what's on receipt

My Daughter recieved an Adidas jersey from her friend for her birthday, however the jersey was too big. We took it to an adidas store at Forest Hikl and requested if we can exchange it as it was purchased on sale. The sales lady made contact with her head office to confirm how to proceed. The lady on the other side of the phone advised her it could not be exchanged as it was on/sale and there is nothing she can do. I requested to speak to the lady who identity herself as the GM named Bernice. She was rude and would not even give me an opportunity to confirm that on the receipt recieved no where does it stipulate this, however it doe stipulate that items purchased may be exchanged by no refunds, this we understood and we were asking was for an exchange. I explained to her that this is unacceptable and her attitude does not deploy that of a GM and that I make this incident known to all as this is really sad that a brand of this magnitude is being displayed as unprofessional and basically misleading consumers. She refused to hear me out, yelled on the phone and insisted I put the sales lady back on the phone, I ended to call with I will now make this public her response I don't care.