T-mobile unlocked iphone didn't come with an activation code?

I ordered my iphone 5s directly from apple. It is the unlocked iphone for T-mobile, and comes with a T-mobile sim card. It comes straight from China, I open the box and start the phone up. During set up, it informs me I have a voice message -- it's from T-mobile with instructions on how to set up. I appear to have all the information, except one piece. The activation code. I try calling T-mobile directly, they send me to the store. Only problem is, the plan I want is only available online.... ensuing huge run around that doesn't matter here. (Though rest assured, both T-Mobile and Apple were consulted)

Bottom line: I have to go ahead and purchase another sim card anyway. Has anybody else had the same issue? - how did you solve it?