Something is really wrong here. WHEN did you get notified that your weapons were seized? The reason I ask is because US CUSTOMS (via the UPS customs agents assigned to their inspections) takes 3-15 days to inform you that your kit has been seized. At this time you should recieve hard copy confirmation that your kit is being held, with a solid reason as to what is exactly wrong with it. Then you have 45 days to respond to this with a form stating that you either wish to personally modify the kit to conform with US law and pay whatever impound fee your kit may have incurred, you wish to forfeit the items to the custody of the government OR you wish to go to court to fight the seizure.
Items held when shipped through UPS are always expedited through Customs process by that parcel agency. They (UPS) GUARANTY via their shipping agreement on their own website that they will contact you and allow you to decide what your wish to do over the seizure (modify, forfeit or fight in court) right after it happens. For customs to say they are going to destroy your items in such short order is AGAINST FEDERAL LAW unless you have already signed papers stating that you remand the items over to the government in forfeiture. You have 45 days MINIMUM to start the process of attempting to recover the goods. They also do not do any neutralization (incinerations) on the 25th of December, the 1st of January, any federal holiday nor US Customs and Border Patrol Inception Day (May 28th 1924), so your items would have been withheld for the next incineration date in any event.
Whenever you are presented with a notice of seizure from Customs, copy it via scanner and send the images to RSOV and they will work to fix the problems.
As a note, I know a lot about The US Customs and Border Patrol/Protection Agency because of a morbid fascination I developed for the agency upon finding out on my 12th birthday that they were founded on May 28th...my birthday, from my Ex-Cop uncle who now works for...you guessed it...The US Customs and Border Protection. If you ever need help dealing with them, PM me.