A consumer is a person that buy goods from you, that is he or she pays for purchasing a product from you, they are called the buyer, on the other hands, a consumer is the one that consumes or uses your goods or products, and they are called the end users. It is not necessary for a consumer to buy goods from you before they consume the goods while a customer must purchase products from you before he or she can consume it. A customer can be a business entity or even an individual, but a consumer can be a family or any group of people.
A customer always pays for the goods or product purchased, but a consumer does not necessarily pay for the goods, like a situation where the good is being given out as a gift or purchased by the parent of a child. Moreover, a customer can buy goods or products purposely for resale, but a consumer gets a good purposely for consumption.