Second hand dirty sneakers.

I went to studio 88 Jane Furse crossing to exchange sneakers yesterday ,as i bought a wrong size for my daughter.. Firstly the sneakers i bought was 200 more that the sneakers they gave to me,i had a size 4,and i wanted size 3..there was a lady who was assisting me,even though i can't remember her name as none of the sales assistant had their name tags on,I told her I want a size 3,she then cane with a box and said it is exchanged,since i was in a hurry since my daughter had to go somewhere i didnt check,i just took the box of the sneakers and went to exchange at the till,the sneakers they gave to me was 200 less than the sneakers i gave to them,they said i'm not gonna get a refund since the 200 balance since i didn't buy the sneakers from their store which wasn't a problem for me but when i got home they gave me a different kind of sneakers but it's a size 4 again .what ****es me off is that the sneakers they gave to me they look like second hand,i had to spend more money to buy my daughter another sneakers since the store kept my original reciept,I dont want their second hand sneakers i want my money back.or they should give me my sneakers and the original till slip,i will exchange it were i bought them.