How do I upgrade my subscription to ULTIMATE?

My Avast internet security subscription renewed about 4 days ago. I also have a 3 year subscription to SecureLine VPN set to expire in 2021. Looking on the website, there is an ULTIMATE bundle which very much interests me. I’ve been trying to find a way to upgrade to Ultimate but can’t see how, nor is there any support email or phone number listed to make the request. How can I do this?

Contact support: https://support.avast.com/contact