I have the same issue. I received the Pz III the week prior, and then later the P-40, both with no issue. However, I am yet to receive the strv m/39 even though my account is linked and I claimed it during the drops.
I waited 2 days, then lodged a support ticket after relogging multiple times and even being offline for a while, and as soon as I had submitted the ticket and went back in, bam, they were there…