I have a Verizon Samsung Galaxy S4 with a Net10 ATT sim. The internet and messaging work fine but the calSl drop after a couple of minutes. I had a LG with Net10 previously and never had this issue. S4 is model SCH-1545, android version 4.4.2, baseband version I545vrufnk1, kernal version 3.4.0, build number KOT49H.I545VRUFNK1. I have it set to gsm/umts and APN is setup with info from Net10's website.