Shipping county value showing as a number
The issue here is common to countries whose administrative areas don't render with abbreviations, which is the case in other countries like the U.S. and Canada where States and Provinces are abbreviated when printed (e.g. SC, NC, TN, etc.). Many of those countries use simple numeric codes or nonsensical alphanumeric codes as an administrative designation but should have the full names of the areas printed for display.

In the Address Field module, we introduced a configuration option for such countries' address formats called render_administrative_area_value that must be set to TRUE to do so. I've opened an issue for Estonia that will also ensure we've done this for the other countries we know about:

https://www.drupal.org/project/addressfield/issues/2983142

I'll have a patch up there shortly. : )