It seems to be Posta connected component, while you really want a wrapped component.
You will need to connect to withRef: true:
connect(null, null, null, { withRef: true })(Post);
then use getWrappedInstance()to get the base connected component:
this.refs[<id>].getWrappedInstance()
docs:
[withRef] (Boolean): true, ref getWrappedInstance(). : false