I was looking around and I think a lot of people are confused when to call customer service and when not too. This should be thread if someone is not sure he can reference. Here goes are 2 I was just thinking of. Feel free to add.
Don't call CS if in the T & C it says your not going to get something and trying to find out if you will.
Don't call CS when there is a price mistake and you want to make sure that its valid and you will receive what ever it is.