I'm in the same situation as you, I'm about 2-3 levels behind because the first batch of loaned units came from the inbox, which weren't sent to you if your account didn't exist before the message was delivered to all players. I've contacted support and been waiting over 2 weeks for a response, didn't get so much as an email just to confirm that they even received my request (nothing in spam either)
I created a new account just to see what it would look like, and yeah it seems like NOW you do receive the catch-up inbox loaned units, but if you created your account about 2-3 days into the era, they did not have that recovery system in place. I should be 2-3 levels higher than I currently am lol it's ridiculous.