Unfortunately there really isn't anything you can do to force anything other than keep sending emails and see what happens. Send internal SFI messages, use chat if they happen to be on.
Also revisit how you are sending messages that make people block you. Are you too aggressive? Too passive? If they are CSAs use the CSA exchange to try to get different CSAs who haven't blocked you. If a PSA no longer wants to be part of SFI there isn't much we can do :(
