Bad service

I bought a pair of shoes for my daughter at Mall of afrika ,and i just realized that the size is wrong and i had to exchange it at foschini in Masingita mall only to found out that i misplaced my proof of purchased and the cashier by the name oF Makhani advise me to call the head office so they can give me my transaction date because i bought it using my TFG account ,i phoned tfg head offfice and the *********** Consultant couldnt help me and i waited for 3 hours and never get helped .And i had to buy another pair of shoes coz thy never helped me for my daughter. I was shocked when they tell me that i can not do an excange for the right size in Giyane cz i bought it at mall of afrika but How? YOUR SERVICE IS SO BAD!!!