Boinquo - what exactly does the tracking say? What makes you think it's stuck in customs?
If it just says "inbound into customs" and hasn't updated in several days, there's no need for panic...yet. Plenty of girls here have posted similar stories, one especially harrowing this past August, and most if not all with happy endings. Sometimes packages just take longer than others in customs.
I once had 2--yes, two!-- separate large boxes "inbound into customs" for two weeks. They arrived with official USPS tape that said "INSPECTED BY USPS CUSTOMS". Nothing was wrong with my bags, no customs fee, no letter or wrist slapping or anything like that. Granted, this was at the height of Christmas season, but still was nervewracking. Try to keep in mind it IS that time of year again. I think it's safe to assume there's already an influx of holiday packages streaming through customs, especially with Thanksgiving and Black Friday less than a week away.
You just simply have to wait. And try not to worry.
Now, a little advice regarding Paypal. Firstly, filing a claim against Jacky is a bad idea. One, you'll automatically find yourself blacklisted (goodbye high quality reps at wholesale prices), and two, you won't get your money back.
Since Jacky has already provided you with an active tracking number that shows proof of shipment, you won't win on the "item never received" claim. Paypal will track the package and tell you the same thing: just wait.
And since you're knowingly and willingly buying replicas, the "item not as described" claim won't fly either. Paypal 100% does not tolerate counterfeit transactions. They can't. It's illegal.
Not to mention, in the event (heaven forbid) customs does seize your parcel, it's certainly not Jacky's fault. Sure, it sucks... but why should he have to be out both the product and money? Once it's made it through their origin customs, there's nothing ANY seller can do or say to the destination customs. It's out of their country and out of their control.
Buying reps online from foreign websites and having them shipped to you is a gamble everytime. We the buyer assume all the risk. Caveat Emptor and all that jazz.