Membership 2 Pro - Problems with Plugin

We're having issues with the plugin. Simply adding a user in the admin is not working. When we try and add a new user on the left, it doesn't activate the button, and returns '1' next to each field. When trying to add an existing user, we get in a loop when assigning them a membership type. We confirm the active dates, then it kicks us back to confirm membership type again.

We're really getting no where with this at the moment. It's a little disappointing.

Can you help?