That would have been the professional thing to do.  Put up a static web page saying "sorry, we have trouble, launch postponed until '.  Then test with staging site to make sure all the kinks are worked out (don't forget to multiply quantity by price, for example).   Don't use wordpress for a site you are expecting to get hammered.  Ideally, you could build a client side Javascript shopping page that directly submitted to walletbit.  The whole thing could be served statically, even a VPS could serve thousands of hits/second.   I could implement such a thing in probably about a day and I don't consider myself a Javascript wizard.

walletbit fails too.  No tracking/order number, as far as I could see.  Their interface is confusing.   I created an account hoping it would give me more tracking for something went funky.  When I tried to order from Avalon, there was no way to pay with my own wallet.  When I finally decided to log out, the option to pay directly to a bitcoin address appeared.