Start the game in iOS, follow the guide on screen, play until you have recruited Hawkeye. At this stage, you should have Ch.1 M.2 available to you.
Click on "Allies"
You should see this
Log into Facebook, give permission to post. After that, you should see this.
Do this by tapping the home button, then double-tapping the home button again, you should see a bar of apps that are running in the background, find MAA, tap and hold until you see the red x, click the x and MAA should be closed.
Now continue gaming until you defeat Baron Zemo, once you defeated him, CLICK EXIT MAP.
Log into FB version on your computer, you should see it in your inventory.
It still doesn't work for me!
You should file a support ticket with PD here  Happy Gaming!