diff --git a/src/sipcentric/__init__.py b/src/sipcentric/__init__.py
index 7ce8006..d4f8e49 100644
--- a/src/sipcentric/__init__.py
+++ b/src/sipcentric/__init__.py
@@ -159,7 +159,7 @@ class APIObject(object):
             raise ValueError(
                 "%s ID %d already created" % (self.__class__.__name__, self.id)
             )
-        self._data.update(**kwargs)
+        self.data.update(**kwargs)
         if not self._data:
             raise ValueError("No data associated with record.")
         return self._create(parent=parent,data=self._data)
@@ -274,7 +274,7 @@ class Customer(APIObject):
     def create(self, parent=None, **kwargs):
         if parent:
             raise ValueError("Customer cannot have a parent")
-        self._data.update(**kwargs)
+        self.data.update(**kwargs)
         for k in ("accountType", "company", "firstName", "lastName", "email", "address1", "city", "postcode", "telephone"):
             if k not in self._data:
                 raise ValueError('missing mandatory field "%s"' % k)
@@ -346,7 +346,7 @@ class LinkedUser(APIObject):
 
     def create(self, parent, **kwargs):
         kwargs['type'] = "linkeduser"
-        self._data.update(**kwargs)
+        self.data.update(**kwargs)
         for k in ("activateUrl", "email", "recordingAccess", "owner", "enabled"):
             if k not in self._data:
                 raise ValueError('missing mandatory field "%s"' % k)