I'm such an idiot. I thought sending it Registered would give peace of mind that they've received it (and to avoid any fraud) but now it seems I forgot to select Delivery Conformation and have no word on knowing if they've received it or not... also it's not trackable. Whereas Express seems to do the same thing as Registered but IS trackable... always thought Registered was the most secure but now I don't believe it is... oh well...