JSF not finding function

Question

I'm having trouble with my JSF prog, it is throwing error msg like this

    javax.servlet.ServletException: /addCus.xhtml: The class 'gDANIEL.CustomerController' does not have the property 'addCustomer'.


root cause 
javax.el.ELException: /addCus.xhtml: The class 'gDANIEL.CustomerController' does not have the property 'addCustomer'.

It is saying that addCustomer method does not exist in the class CustomerController, I really don't understand i've checked and in fact it does exist

CustomerController

    public String addCustomer() throws Exception{
    CustomerManager cusMgr = new CustomerManager();
    cusMgr.addCustomer(customerID, customerFirstName, customerLastName,customerAddress, customerPhone, customerEmail, notes);

    message = "Record Successfully Saved";
    return "add";
}

jsf page from where I'm calling the function

    <p:commandButton value ="Save Customer Information " action ="#{customerController.addCustomer}" update="outputmessage">
    <p:confirm header="Confirmation" message="Are you sure?" icon="ui-icon-alert" />
</p:commandButton>