If you are a Premium user and you see a Payment Wall when using Hotspot Shield, you might not be signed in to your Hotspot Shield Premium account and Hotspot Shield is in FREE mode. A reason to this is because you have recently updated the Hotspot Shield on your device or you have installed Hotspot Shield for the first time.
To bypass this payment wall/7-day free trial page:
Start by swiping left until you get to the last page
You will see a faint Grey "X" at the top right. Click the "X"
On this next page, you'll need to scroll all the way to the bottom
When you get to the bottom you'll see another Grey "X". Click on it. 
Now all you need to do is sign in with your Premium credentials
If you need help getting signed in you can take a look at this help article below.
How do I sign in to Hotspot Shield?