In July, I got a dunning letter from FedEx that I haven't payed a bill. I did receive a parcel but never had received the initial bill. So I payed it right after the dunning letter. I did however get more dunning letters and called FedEx. The lady on the phone told me I should use the form for exactly this case. I did and never had an answer from Fedex (although they claim that they will contact you withing 5-10 days in a standardised email!).

Now I got an insanely high bill from Debitors Management AG. I instantly called them to tell them, that I payed already and that I also used the form on FedEx's website about this matter and that I won't pay anything and will consider legal measures in this case, if it doesn't get solved.
The guy on the phone who spoke really bad german then said: Oh right, I see now that you payed it. Don't worry, we'll halt further dunning letters and legal steps.

Then, because I already was documenting this case (as FedEx never replied but happily also plastered me with dunning letters), I asked for the name of the guy at the other end of the phoneline (the debitors.ch guy). He wouldn't give me his name but instead said, there's a name on top of the dunning letter you received... I misread the name on purpose and the guy on the phone said: Yes, that's me!

What a scam!
I am still trying to get in contact with FedEx and wrote a mail (from my spam address) to debitors.ch as it says in the letter, that only written protest (within 10 days) will stop further legal actions. I demanded a confirmation that my "case" is closed!

Let's hope, this dunning nightmare ends. Otherwise I will have to get legal help.