8 minute rule cake

So I bought a terimasu cake at canal walk Woolies didn't check that the sell by and use by date is the next day, okay since am closer to Vangate went there for an exchange cause I still wanted the cake by not a used by date so close,when I reached customer service the called someone working at foods and he just said 1 I did not buy the cake there, 2 I can still eat the expired cake it's still okay, I told him that I was uncomfortable with even eating a R170 cake whereas it's use by date has reached,he proceeded and said even the 8 minute rule won't allow him 2 take the item, okay now my question is why put in the use & sell by date if the item is still okay for consumption and why am I told that I did not buy the cake there,where is that on my till slip and what am I going to do the the cake and what is the 8 minute rule is there somewhere Woolworths customers go 2 get educated about such????