If a customer is not happy then they will go somewhere else, and tell their friends to go elsewhere too.
It's a package.
Make sure whatever you are selling is good quality and good value.
If a customer complains about something then really listen to what they say - give a refund without question if appropriate, and change your product or service if necessary.
Customer satisfaction to me is, going that extra mile to ensure the customer is happy with their product/s they have purchased and the service given is polite and professional.
If you value your customers, nothing is to much trouble.