You can call Customs and ask them what's the delay? I don't think 10-14 days to clear thru NY is outrageously long.
But you may be able to answer your own question. How much did you order???
ADC doesn't carry any item that would be restricted for delivery in the USA and I've never had a problem. But I also am aware that you can only legally import a 90 day supply of any medication into the US.
If you exceed that 90 day supply it can be held and yes you're unlikely to get it released to you. You're lucky ADC is replacing the order. They don't have to. They are not liable for Customs actions.
I cringed when I read a post here that said an online blogger was accepting ""group or quantity orders"" thru her website to avoid high shipping.
That's just asking for problems.