Can't send or receive SMS, can't disable Voice+ in CM11

A couple days ago I installed CM11 on my Sony Xperia T2 Ultra. I recieved one text from my provider (TalkTalk) and have been since unable to send or receive any SMSs. I can still call and get called, as well as use mobile data. I think I've narrowed the problem down to Voice+ being enabled, and at first the disable option in the app menu was greyed out. I installed Google voice from an external site, and now Voice+ shows up under "Wireless & Networks", but even if I select the disable option it keeps the "Enable all apps to send SMS through Google Voice" text, and I still can't send SMS. I really want to be able to text but I also don't want to downgrade back to the default ROM.

Thanks in advance for any help.