Unsatisfactory food and personnel customer service

I bought banana bread on 09.06.15 at Spar Secunda, Mpumalanga only to find it had a plastic object inside after slicing it. I then returned it the next day to customer service. The woman who I spoke to asked me with attitude whether I want to take another one or get my money back. I asked her what is their procedure to handle something like this, how do I know if I take another one I won't find something inside. She told me I will open it and cut it up there and then to check. She then returned my money and without an apology I left.