I then contact the European Consumer Center (France) and explain my case, the servers of Stuxhost not being in France I am explained that the organization must contact "their Dutch counterparts" to try to resolve the problem with the company concerned (#Stuxhost).
As you can see, at the time I was so lost, that in the process I only indicated that I had been charged once in duplicate, when it is much more than that.
Today I received the answer from the European Consumer Center (France) and after #Stuxhost was contacted by them, he finally refunded me!