Your problem is with your Ajax.BeginForm; you're not actually telling it to send a request anywhere.
@using (Ajax.BeginForm("ACTION","CONTROLLER", new AjaxOptions
{
Confirm = "Are you sure you want to send this message?",
HttpMethod = "Post",
InsertionMode = InsertionMode.Replace,
LoadingElementId = "loading",
UpdateTargetId = "messageForm"
}))