The Secureline VPN is a paid product, so it shouldn't just install that you have to either use the trial version (and you agree to than and complete a payment mandate for when the trial ends).
I don't use Avast Premium, so I can't say what it is that you are experiencing. But in the Avast Free version there used to be elements that are also paid version upgrades in the hope you would purchase. Such as the ones with padlocks in the attached image.
Is that what you are seeing, as this isn't the full program, just an enticement ?
How are you seeing this presented ?