You're definitely supposed to get a confirmation email, number, et cetera after purchasing the priority option--you have to attach the receipt of purchase and write the number on your envelope. Iain, I hope it goes through fine for you, because this is definitely seeming to be quite the hassle if it doesn't immediately process in the correct fashion.
Calling Worldbridge wasn't a massive pain, my connection was bad but that isn't their fault--however, I was just told that "the error would be reported to the consulate and they'd get back to me as soon as possible." Doesn't exactly invoke a lot of confidence.
My only issue here, really, is the whole 'purchase on the same day you plan to send your application off' thing. I wouldn't mind waiting to get this sorted out otherwise, I understand errors in newly implemented services. I suppose, I mean, they did take my money (and the call's 12 dollar charge was added almost immediately as well); so at the very worst, they'll refund me for today's purchase and I'll do it again another day. Just more waiting added on to a process that could very well give you an ulcer when it comes to waiting, haha.
edit: in case anyone in the future has a similar issue, or is worried that they may encounter the same problems, here is just some brief addendums:
-The browser I used while doing the transaction was Firefox, latest edition as of July 12th, 2010.
-The error message was something to the effect of "Object not found, technical department has been notified of this error."
-Within minutes I emailed Worldbridge through their "Contact Us" form, received standard form email back with 'case number'.
-About 30 minutes later I called the given number, had real trouble on the line understanding the woman/being understood (this was all connection based, and actually seems to be a problem on Worldbridge's side, as my fiance later calls and has the same issue)--after some time giving details such as my credit card info, what I had purchased, and my application GWF number, I'm told that she will contact the consulate and they will get in touch with me "as soon as possible". The problem here being, it's already near 5:00 p.m. in Chicago, and a caveat of the priority service is that you must send your documents in the day of purchase. Presumably, I will not hear back from them in time to send my documents in today (last express pick-up in my area is 8:30, but I would assume office hours have ended at the consulate), therefore, totally in a bind.
-My fiance also calls, gives same information, receives same answer. Consulate will be contacted, you'll hear from them when you hear from them.
Doubt I'll be hearing back soon enough to turn in my documents today, so let's hope they recognize that, and just refund me the charge--and fix the cart error--and allow for me to purchase the service again tomorrow. Boo hoo.