You can contact your branch office directly or contact the customer support hotline.
If you want to find out which branch is responsible for you, or who your direct contact partner is, you can click on the "Contact Person" button on the starting page and you will be shown the appropriate contact details. If you are an existing customer with you own personal contact, you will see the person's direct contact details.
If you have technically related problems with the online shop, you can contact your customer service as usual at +43 (0) 720 115 055 or by e-mail.