I brought a pack of ...

I brought a pack of 5 jockey panties ...total cost of R 449.00. I know my size...so not necessary to fit...at home ..i want to wash it before i wear it and then i saw it is not the bikini but full briefs...i gi back and try 2 explain that i took the wrong packet and want 2 exchange for the right one...the lady inform me the companys policy nk underwear exchange but she can see everything was just as i brought ....and that i did not wear it.....with the same words she said they will maybe change a bra.... so what what is the differwnce between panties and a bra which one is not underwear.... i dont wont the money back i just wont the right fit....and i feel the personal can see uf a thing is use or not.....she also said its my problem i must took the right packet....but on their shelves the packets was not nice together and i took the wrong one by mistake...