Hey, did you get this resolved? Had the same issue today and found a suggestion to "remove the unit number or apartment number from your billing address". It worked for me and payment went through.Give it a shot if you're still waiting for a mod.
By any chance are you in downtown Vancouver?My coworker and I had this issue until I left work.I'm in Burnaby now and the issue seems to have gone away for me while he's still at work and sending everything three times.
My coworker (who I convinced to make the switch) complained about this problem on his iPhone today.Outgoing messages fail, but the recipient receives the message 2 or 3 times. I tested with my android phone and sure enough the same thing is happening...