Galaxy S6 :: Sending Duplicate Messages

So I've had my s6 since April when it came out. I'm on virgin mobile in Canada. 3 days ago it started telling me my messages have failed to send and sometimes I'd get the 'service currently not available will resend when network becomes available'. But the thing is when I would get those messages the texts were actually going through and the phone would send duplicates of these messages without my input. Now it's sending duplicates regardless if I get those failed message notifications. I've factory reset the phone twice. I've hooked it up to the computer to see what's going on and to see if there is an update. Both the computer and the auto update option say I'm up to date. Phone is not rooted. Running Android 5.0.1. I've called tech assist and I've replaced the sim card.