Help needed with system updates

When I purchased 1 x eM Client 8 PRO it came with lifetime updates.
All has been well until today when I attempted to log on and I encountered this message.
I do not understand as I purchased with lifetime updates.
How can I fix this.

The license you purchased in August 2020 is a version 8 only license. You can use that indefinitely with version 8, but you can’t use it with version 9.

If you still have the confirmation email from the purchase, and it specifically says lifetime upgrades, contact me directly on

Thank you Gary for your prompt reply.
I shall go through my old paperwork and send directly to your email