diff --git a/source/app/models/main.py b/source/app/models/main.py
index ae915c7..5fdb284 100644
--- a/source/app/models/main.py
+++ b/source/app/models/main.py
@@ -5939,7 +5939,9 @@ class CfdiNomina(BaseModel):
                 (CfdiNomina.fecha_pago==values['fecha_pago']) &
                 (CfdiNomina.fecha_inicial_pago==values['fecha_inicial_pago']) &
                 (CfdiNomina.fecha_final_pago==values['fecha_final_pago']) &
-                (CfdiNomina.total==values['total']))
+                (CfdiNomina.total==values['total']) &
+                (CfdiNomina.cancelada==False)
+            )
             .exists())
         return result
 
@@ -6076,6 +6078,13 @@ class CfdiNomina(BaseModel):
         )
         return {'ok': True, 'rows': tuple(rows)}
 
+    def _validate_timbrado(self, data):
+        receptor = data['receptor']
+        if receptor['TipoContrato'] == '99':
+            del data['emisor']['RegistroPatronal']
+
+        return data
+
     def _make_xml(self, cfdi, auth):
         emisor = Emisor.select()[0]
         empleado = cfdi.empleado
@@ -6280,6 +6289,8 @@ class CfdiNomina(BaseModel):
             }
             incapacidades.append(n)
 
+
+
         nomina = {
             'nomina': nomina,
             'emisor': nomina_emisor,
@@ -6289,6 +6300,7 @@ class CfdiNomina(BaseModel):
             'otros_pagos': otros_pagos,
             'incapacidades': incapacidades,
         }
+        nomina = self._validate_timbrado(self, nomina)
 
         data = {
             'comprobante': comprobante,