Call options keep resetting

[Guest jaymz462]

I've got an unlocked BJII I'm using with T-Mobile. Whenever I reset it, my settings in Settings -> Phone -> All Calls -> Call Options revert to factory settings, ie, the "Show SIM contacts" box is checked and the Voice mail number isn't what I want it to be. I'd like to keep the SIM box unchecked and have my custom voicemail number still there after reset- is this possible? I've googled but haven't been able to find anything.