I'm trying to submit my form to "NewCustomer" action in "CustomerListApiController"

This is where I'm trying to route my form

Html.BeginUmbracoForm("NewCustomer", "CustomerListApi",  FormMethod.Post, new { @enctype = "multipart/form-data")

I have a button of type="submit"

When you click the "Open form" button on my page an Ajax-post is triggered to the "Modal" Action in "CustomerListApiController". The method returns the requested data and a modal with the form is shown on the page. But when I inspect the form element it says that it wants to post to "Modal" action again. Despite that I've specified "NewCustomer" in BeginUmbracoForm.

My controller

public class PatientListApiController : SurfaceController
{

[HttpPost]
        public ActionResult NewCustomer(CustomerBE pCustomerBE)
        {
             //Do Stuff
}

[HttpPost]
        public PartialViewResult Modal(int? Id)
        {
             //GetData and return model for rendering the form in a modal

        }
}

What I'm I doing wrong?