In my case, I didn't even get a message about it in my mailbox.
Same thing happened with the Silver Eliza pf just now: the mail is totally missing, even though I scored some points from defense wins (enough to complete the first few milestones at least). That should be enough to get a message saying 'you didn't earn enough to get ranking rewards', but that mail never arrived.
I'll send in a Contact Us report soon so that this situation can hopefully get sorted out.
EDIT: False alarm, the Silver Eliza message did show up eventually. But I'm still missing the Silver Squigly message so I'll send in a report to get that sorted out.