Call to Functions Membership 2

How can you possibly create a whole new product and then leave us high and dry. I was using the first version of your membership plugin with success, using my own code to call your functions that retrieved info such as user subscriptions and memberships. Then after updating to Membership 2 I find that all this is irrelevant as the whole structure is changed but there is no documentation anywhere.

How do I retrieve user info? I have seen previous posts about class names changing and using functions such as current_user_is_member() to no avail.

Why can you not provide clear documentation on how to use the new calls, this way in one go you could stop all the questions being asked on the same thing!