You can contact Apple's customer service for sales and technical support via live chat through the Apple website. For sales customer service, choose a product category at the top of the page, and select a specific product. The chat option is available at the bottom of the page.
For technical support, click Support at the top of the Apple website, and select a product. On the product's support page, scroll down to the bottom, and click Contact Support. Choose a topic category, and then select a topic. Click the Chat option to start a chat session with an Apple specialist. The chat option is available for certain topics only.