Expired / Rotten items

I'm writting here with a heavy heart for negligence in Shoprite West Street, does it mean when you buy something there we must also reserve money for going back to complain ?? It's not the 1st time in October I bought can of Sprite from the Liquor shop on the 24 can itself best before was the 19 and I didn't check only realised when was very far. Second incident I bought fresh milk on the 4th of December and best before date was 14 /12 took it home to my surprise milk was off already went there the following day and i was so mad previous day had to select as could see that this milk is not right from the fridge, manager that was on duty called the guy work in that Dept his excuse was fridges were full so they use fruit and veg fridge that's the reason Milk is off, instead of this manager sorting my query and deal with his staff made wait while arguing. I used my money to go and complain for their fault instead, my time not like I had nothing to do even if the milk is small I did not get it for free, let your staff do their work nobody has money to run up and down returning things as if it's my fault. I have pictures for both incidents as proof (till slip, can sprite, milk as well the bar code)