Hello, I've not tried to withdraw BTC before from this site. After setting up google authentication, I keep getting errors when I try to do so however, is there an issue with the service at the moment?

There is no issue with the service.

On the security page: https://dispenser.tf/view_security/ , make sure you have "Use Google Authenticator" enabled. When you access your shop you will be asked for the code. Check if your code works.

You could also try to put in the code not immediately after its generation (like 15-20 seconds after) and see if it is a clock synchronization issue.