In this article about how the SpaceX anomaly will affect Iridium it says:
In its official website, Iridium describes itself as "the world's only truly global mobile satellite communications company." It offers global voice and data communications coverage.
Is Iridium the only mobile satellite communications network that has polar orbits, and therefore has line-of-sight service to satellite telephones at the poles?
Quote and screen shots from: https://www.iridium.com/company/companyprofile
Reaching across land, sea, and air, including the polar regions