Hi @Myriam99, sorry to hear about this. 
I have translated your question to English as this is an International forum, please post any replies in English and it will be easier for me and other users to assist you.
Have you had the chance to try with a different USB cable? Just so we can make sure that it's not the cable that is the cause.
You can also take a look in the charging port to make sure that is there no dirt or dust inside of it which makes the cable not stick in place.
Let me know if that helps!
0online
1869689posts