My french diploma

I still have not received my diploma certificate and the official results of my French exam!! 🤷‍♀️ I got really annoyed, not because of the delay, as I know it is not the institute's fault, but rather, at their lack of feedback about the delay, because it is their fault that they are not following up properly.

So I wrote a strongly worded email... Only I don't know how to write a strongly worded email in French 🤷‍♀️... So I only wrote the greeting and best regards in French, and the rest in English 🤣 They are probably laughing at my email.. If I were them, I'd be like; first learn how to write an email in french, then demand your certificate O.o