If you have any issue navigating the website either it be signing in, checking out, adding products to cart or any other technically difficulty please just create a support ticket.
Please include exact details you are facing and how to replicate them on our end. The more details the better to try and solve the issue. The more details you provide will also make sure we can solve quicker.
The browser you are using and device is helpful. Screenshot of the issue, "I'm on this page and it does this or page is blank, which page, ect.. " The More details the better.
Your ip if you know it. Step by step details of the problem.
You can follow the below link to learn how to submit a support ticket if you don't know how to.