Flop

I bought a fuel pump at Midas Model park Emalahleni on 29/09/2022 it doesn't match the one in my car by looking at it I didn't open the packaging. Today on 05/10/2022 I tried to return it they are telling that I should have returned it within 3days time but when I checked the invoice it says no refunds after 3day I told them that I don't want a refund I want to exchange it to something else and they said no it can't happen... Today is my 7th day with this product and last time when I check SA return policy says 7-14day return I don't know how come Midas makes thier own rules are we living under Midas rule of law or SA?