Lifetime Licence for my PDF Achitect 4 has been refused

I purchased PDF A 4 some years ago and added modules, and I was given a lifetime licence. I have just upgraded my computer with a new MB etc, so I was forced to email and ask for a new key. I have been told that they will no longer support 4 but for a special price of £55 I can upgrade to V8, well I did that and found to my horror that is now a subscription, there was no warning of this in the email and constant emails back and forth have made no difference.

I said that I purchased a lifetime key and as far as I am concerned I am still very much alive.

Can they legally do this as to my mind they have cancelled the agreement with no input from me?

Kind Regards