Thanks @naomicbush,
Yesterday the form wouldn’t confirm after sending.
In my contact message I wasn’t describing the trouble, just asking how to contact the support. What is more convenient for you in order to exchange about my problem : using this forum or email ?
BTW, since I am in a kind of emmergency here, I also opened a help request on this forum with more decription about the bug, please have a look here : Need someone to fix Add on "Send to Third-Party".