I have that same problem but my subscription ended yesterday and the problem still exists. I have installed all the other apps from TOTAL but cannot install Freedom to my iPad. It is in a loop. Subscription expired, buy a new one, directs to My F-Secure, I install Freedom and get again the message subscription expired, buy a new one...
Most probably you might have purchased our app via App Store or using the F-Secure Total subscription before. There is a grace period to log out from the subscription for App Store and for F-Secure Total, you are able to log out from the subscription if you have a newer version of F-Secure FREEDOME VPN.
Please follow the steps below :