I am posting here as ACYMailing are not giving me any support on this issue. Apparently they have higher priorities than providing support to paying customers.
I am using Joomla 5 and for the last few versions of ACYMailing, the update site disappears from the update sites list in Joomla. This means I am only alerted of ACYMailing updates when I directly go to the component. Of course it is not practical to login and go to all the components on a regular basis to see when updates are available and practice good house keeping with your website to avoid being caught out by vulnerabilities. No one has time to do that and this is why Joomla alerts you of new updates to your extensions on the Joomla dashboard when you login.
All the official support team have offered as a solution is to reinstall ACYMailing - which I have done repeatedly but within 24hrs the update site disappears.
So I was wondering if anyone else is having the same issue or not?
As I've explained to support - I'm not trying to be difficult. I simply want an extension I have paid money to work as expected.