I just returned to the US from another country. I took out that country's sim card, and replaced it with a sim card that works in the US. To my dismay, about half of my sms contact names in active sms threads have been replaced with a phone number. The people who I messaged while in the US, still show the contact names, and about 1/2 of the people who i messaged abroad still show the contact names in the SMS threads, but then about 1/2 of those people I messaged abroad, have been replaced with their phone number. I even tried to re-add them in to the phonebook, and those people still show as only a phone number, even though I double verified that they are all in fact in my phone book. Any ideas?