I'm using a Samsung Vibrant on an AT&T Straight Talk Sim. It worked great for the first week in all respects - save my phone would get stuck in 2g if I entered a 2g area and would then have to reboot to get back to 3g - not too big of a deal.
In any case, my outgoing texts stopped working yesterday. Incoming texts work fine. Incoming and outgoing MMS work fine, internet and calls are fine. Just no outgoing texts. Other people on other forums are telling me I have a bad sim card. Per Straight Talk customer care, I removed the sim card and wiped it down with microfiber. I also tried updating the SMSC number (*#*#4636#*#*) to a number the rep gave me, but it won't update the number - just gives me an error message. If I hit refresh, it reads 00. Keep in mind the outgoing texts were working fine until yesterday. I've also factory reset the phone several times in the last 24 hours, doing clean wipes. Nothing seems to work.
Help!

-Ezra