Q: Problems sending an imessage to a specific contact

I have been having trouble sending imessages using my iPhone 5s to a specific contact. Other contacts do not seem to have this issue. Here are some of the troubleshooting steps that I have tried to resolve this problem:

1. Restart your device.
2. Tap Settings > General > Reset > Reset Network Settings on your iPhone.
3. Make sure that the contact trying to message you isn't blocked in Settings > Messages > Blocked.
4. If the issue occurs with a specific contact or contacts, back up or forward important messages and delete your current messaging threads with the contact. Create a new message to the contact and try again.
5. If the issue occurs with a specific contact or contacts, delete and re-create the contact in the Contacts application. Create a new message to the newly created contact and try again.
6. Back up and restore your device as new.

None of these steps seem to work. When I restored the phone I used my oldest iCloud back up. When I use my MacBook I can imessage the contact but not with my phone. The ios is version 7.0.4. The only thing I can think of is to restore the phone as a brand new one? Any suggestions would be greatly appreciated. 

Thank you!