What substance were you ordering? What return address was on the letter and was it delivered certified mail (did you have to sign for it?). Also, which vendor were you using (this isn't a sourcing question, I ask because there are tons of scam vendors online and I was curious as to whether it's one I've heard of)? Darkweb vendors are more prone to confiscation because TOR/Onion browser has been compromised for years. If ordering from a reliable, trusted online vendor is much safer because, at least in the U.S. , the "not for human consumption/research purposes only disclaimer makes it pretty hard for authorities to actually prove what you're going to do with it. In general, if a non-darkweb vendor promises you the sun, moon, and stars for cheap and/or offers to ship you scheduled and/or illegal products (especially without telling you to check your country's laws before ordering), it's probably a scam (for example, offering to sell you Acetyl Fentanyl, which has been emergency schedule 1d in the U.S. about a year ago, for $30 a gram, or they offer heroin or regular Fentanyl, etc...... If it sounds too good to be true it's probably not legal. I had one good, reliable, honest vendor but the guy quit the business (for unrelated reasons) a month ago so now I am unfortunately without an opie analog vendor (which I really need because I'm simply under medicated for severe chronic pain and it's hard to find someone I get a good vibe from enough to risk my money).
The frequency and quantities of your orders can also play into legit confiscations. If you do like I was doing and just ordering random grams or two here and there, your chances of a package from a legit vendor coming under scrutiny are pretty slim. I have seen vendors who advertise on a professional looking website that have been in business at least a few years say they guarantee their stuff to pass customs. Some will even label it as a different chemical and, if for some reason it doesn't pass customs, they offer to replace it free. I still haven't tried any of them. My one guy proved himself trustworthy and it sucks he quit the business. If you ordered an RC that was advertised/labeled as "not for human consumption" from a regular web vendor, the chances of any charges sticking would be improbable. Take that info as you will. Hope it helps.