After the 6.1.3 IPhone update only one of my contacts does not receive my texts. Sending and receiving texts works just fine with everyone else. I receive this contact's texts, but he does not receive mine. When I send texts to this contact I do not get an 'undelivered' error message. I seems to send just fine, but he doesn't receive them. Neither one of us has blocked the other. We checked.
I have texted back and forth with this contact for months prior to the update, but I verified the number anyway. I powered on and off, tried the method of holding the home and power button for 10seconds, deleted the contact and prior messages then re-entered the contact, and also reset all settings.