Hi @graffix87 & welcome to the forums! 
Slow download speeds have often been reported and have many causes. This article may be of interest to you:
How to improve slow download speed – Microsoft Flight Simulator Support (zendesk.com)
If none of the steps in the article help, you can ask for help from fellow users in User Support Hub > Install, Performance & Graphics
However, before you can post a question, you will need to be at “Trust Level 1”. You can read about trust levels here:
and how to navigate the forums here: Official Microsoft Flight Simulator > Forum Navigation
Hope this helps!