Unfair practice by spar tasbet Park emalahleni

My name is Thembi Mosotho staying in emalahleni I bought groceries at Spar tasbet Park in emalahleni and bought the R70 school shoes that I will donate to a child that is in need of the shoes I found one child to donate the shoes too but the size it's big I bought size 1 o need 12 they refused to change this for me saying I should have brought the child when buying really how is that so the child must go to school without shoes while I have a pair she can use but you said it's donation I'm doing that donating to a needy child please help before school reopen