Customer is who purchase the product, consumer is the end-user, the actual person or entity that will use it.

If you buy, for example, a Samsung TV from Walmart. Walmart is Samsung’s customer, but they are not the consumer. Walmart, in some fashion, is paying Samsung for that TV and reselling it to you. You are the consumer of that TV and a customer of both Samsung and Walmart.

Hypothetically if you’re gifted a Samsung TV and spent no money on it yourself, you are technically a samsung consumer, but not a customer.

In common usage, the terms are often going to be used as synonyms, if you have a problem with your TV you’re going to call Samsung customer service, whether or not you actually are technically a customer.