Well done.
No matter where you are interviewed, it is essential to be dressed smartly and have a clean appearance.
You can expect to be asked about hobbies and interests, why you want to work for the company, and about your willingness to learn, as well as communication skills and your experience of customer service. If you do not have any, say so, but explain in detail what you as a customer would expect from someone serving you, and say that you aim to mirror this behaviour.