Heart of darkness

Hello everyone!
I'm reading Heart of Darkness, which has some exercises at the end of every chapter. One of these exercises is to pretend to be Marlow and write a letter to the European Council to inform them about what is happening in Africa. So, here is my letter. I hope you correct it!

Dear Sirs of the company,
As you know, I was hired to sail a steamer up the river to the inner station, but there are strange things happening here that I believe you should know about. When I arrived here, the steamer was in a horrible state; it was on the bottom of the river, dirty, and full of mud. I started working on it, but when I asked the agent company in the station for rivets, he told me that he couldn't take them, even if there were a lot of rivet packs all along the river.
Nobody here seems to want help me to reach Kurtz and the inner station. I think the station manager felt threatened by him because Mr. Kurtz seems to be the greatest ivory catcher in the whole region. Mr. Kurts also seems to have destroyed the plan of the station manager and his agent to control the zone by themselves.
I hope you will take all the necessary actions to discover the truth.
Greetings,
C. Marlow.

I know it's very long, so I really thank you!

I'm unsure if I maintained your desired meaning at the end of the first paragraph (with the rivets) because I was confused about what you were trying to say. But, the rest should be good. :)