While Windows 10 Creators Update (version 1703 or build 10563) will start rolling out for the majority of Windows 10 users today, the same update for Windows 10 Mobile users will be released two weeks later. According to the official blog post, Windows 10 Mobile Creators Update will be released on April 25, 2017 and only a small number of existing phones will receive it. The update will be released in several waves just like the last time, which means your device may receive it even later, and not on the day when the rollout starts.
Earlier this year, Microsoft announced that its customer care services for Lumia and feature phones will be operated now by a German customer care company B2X. Right after the original announcement, B2X officials promised to release a "self-help" app for existing device owners and it's now available for download from Windows Store, offering a set of tools for customers to diagnose a problem in several possible scenarios.