selling unpair shoes to client

mother in law bought a pair of texan ***boy boots from supplier as a gift for me but upon inspection we noticed the one is a size 7 and the other is a size 5 shoe. I reside in Port Elizabeth and contacted the shop in Bloemfontein and was given the run around that i must phone suppliers myself in an attempt to assist me. after numerous phone calls to JHB and Cape town I still have no way in which this problem can be resolved. The lady at the shop even went as far as to say it is not her problem that they have actually sold these shoes like this to their clients. i have feel a lot of money has been spend on this pair of shoes and you cannot even give it to some as i do not know of a person with one size 7 foot and one size 5 foot. would like to know how this matter can be resolved after all your clients is your bread and butter and not having the attitude you doing your clients a favour by selling them these tipe of products.