After the incident between 
Max Verstappen and 
Lewis Hamilton during the GP of Great Britain, 
Toto Wolff contacted race director 
Michael Masi to ask if he had read his email. This was not the case, so Wolff went to explain it personally to the stewards. What exactly was in the email?
Mercedes sent diagrams to the race committee, which showed that a corner belongs to the attacking party if he is next to the driver in front by half a car length. With this 
Mercedes wanted to prove that the corner belonged to Hamilton and therefore he was not guilty for the crash of Verstappen.
Motorsport-Total.com has investigated the mail and it appears that the diagrams are not part of an official 
FIA document, while Mercedes suggested that they were. The 
World Automobile Association stated that the diagram "has never been an official 
FIA document" and that it has never been published as such, it says on its website.
 Wolff used an informal document
It turns out that the publication is from years back, when Hamilton and 
Nico Rosberg had a fierce duel. Based on that, Mercedes wanted to set guidelines on how drivers should race each other. Mercedes would have used the same document at 
Silverstone as evidence against Verstappen, but it was informal. It seems that there was a miscommunication. Mercedes assumed that it was an official document.
For Masi the diagrams of Wolff were a mystery because they were never part of the F1-rules of the FIA. In the end Hamilton received a penalty of ten seconds.