might depend what part of this country you're in; have you gotten any notices about it or (dog forbid) a tracking # to watch? there are major pile-ups of USPS packages including priority, express, overnight, int'l in some of the biggest distribution hubs for months now.
frustrating as fcuk. I've never known anyone who got a pk seized by customs with small amounts to get anything but the letter, happened to a good friend/neighbor a couple years ago. personal amounts *usually* aren't worth the time and effort for anything else, they want to catch resellers they can pin intent to distribute charges on and sixty ain't gonna do that. hope it comes thru for you sooner than later w/no bullsht!
Assuming you're in the US, the gov't doesn't fuck around at all with fent, which is probably what your "oxys" are. They foam around the mouth for that shit even with smaller amounts so you really should clean house just in case. If this is your first seizure and you invoke the rights to both silence and a lawyer then they probably won't be able to make anything stick tho.