I import a lot of things from ebay (ebay uk)
I never had to visit the customs department coz the parcel always comes home by postman & i never paid a penny on duties. Sometimes the parcels get delayed (due to customs people people playing pata pata poon poon with the packet, they do open it & repack it with indian foreign parcel tapes) & attach some sort of paper & put an invoice like thing on which you've to sign.
Make sure the thing you buy doesnt cost over 10k rupees, else customs will surely come into your romantic movie as a villian, altough 5 of my parcels got misplaced till date, but hey i got 30+ of them

as for the missing i pay by paypal so claiming a refund always worked (provided your paypal account is based on real information, i mean if it gets limited you can provide electric bill etc etc)
As for the customs part, i asked my postman visiting local post office on 27th June
me : Mera parcel nahi aaya, 1st June ko dispatch kia tha
PM : aa jayega
me : par abhi ek mahina ho gaya hai?
PM : kahaka parcel hai?
me : uk ka
PM : customs mein hoga, humlog ke paas jo bhi ata hai hum pahuncha dete hai, customs is beyond our control
Its not once but i visited them thrice, so the post office cannot do anything about the customs. either you'll get the parcel with an invoice (possibly you have to pay duties, am not sure how much and through what mode because i never paid it, so am clueless on it)
Even the seller cant do anything because he cannot control customs, his responsibility gets over once he ships it, and if its insured he is responsible to get u back the refund. since in ur case its with the customs, its not misplaced.
either wait for a few more days or get hold of a clearing agent, he'll act as a savior in your story.
Good Luck