IPhone 5s :: Siri Knows Relationships But Doesn't Find Any Numbers

I loved to tell Siri to call my wife/spouse, write a message to my brother and so on. But since a few weeks, don't know exactly since when, Siri keeps telling me, that she doesn't find a phone number or email address for abc (where abc is the name of my brother, wife, child, etc) although my contact information is set in the Siri settings and all the relations are given to my contact.

As mentioned in the community, I've turned off Siri, reset my iPhone and turned on Siri again. I've deleted all relations in my contact and set them up again. Someone suggested to delete middle names from all contacts, but I'my not using middle names. So, nothing fixed the issue yet. Â

Info:
iPhone 5s, iOS 7.1.2