FluentFormConfirmPhoneField.php

add_filter('fluentform_validate_input_item_phone', function($errorMessage, $field, $formData, $fields, $form) {

    $target_form_id = 302;
    if($form->id != $target_form_id ) {
     return $errorMessage ;
    }
	
	var_dump($fromData->form_fields);
    
    if( $formData['phone'] !=  $formData['phone_1']  ){
        $errorMessage=  ['Error! Phone does not match'];
    }
    
    return $errorMessage;
}, 10, 5);