I'm having issues with my commissioner currently as well. :/
I paid half of my commission upfront in August 2011. She had a few other's going on and asked nicely if it could be delayed which I agreed to since my con wasn't until April.
It is now 3 weeks until my con and I have heard very little but excuses of why things have gone the way they have. I asked that it be done before March and here we are Mid-March almost. She says it will be to me before my con, but I am so stressed, I don't even feel it's worth it.
You know you love me ;3