i do my best to buy hand to hand, and agree with the shop that i pay the price at the time of exchange,
but it seems online delivery in the time of internet is almost unavoidable as technically, it's guaranteed by the carrier to full cost and yours as soon as they obtain proof of posting.
Allah a'lam though, as there is a hadith describing umar (ra) forbidding a similar situation (below).
i prefer hand to hand - though i have bought a couple of coins on ebay in the past.
also leaves no silly records for them to log as there was once a gold confiscation in the us by fdr - where they scammed it (forcefully took it at a low price and sold it back to people at higher prices.
the bullion vault thing is something i dont agree with as it is exactly how usury based banking came about, where the goldsmith realised that people were trading his receipts in the market rather than pick up the gold and someone else re-deposit it.
once he realised that only 10% of metal was ever collected, he began to lend it out on interest, and rather than the people paying him to safekeep it in his vault, he paid them interest not to collect it. then he went as far as handing out more receipts than he had gold, since people were so used to his useless paper cheques, that they were forgetting that paper was a receipt for gold and silver and began calling it "money" rather than a receipt for money. thus was born fractional reserve lending.
and anyway, the purpose of the people having the gold and silver in the islamic system is so that the economic power remains in the hands of the people.
you can understand the situation simply by asking them if they'd refuse to comply if the government demanded (through new legislation) the money of the people which they hold as a trust - and i'm sure you already know the answer.
the lady i spoke to told me that it was kept in safekeeping but was mine, i asked if i could pick it up anytime, and she said - with a fee.
the purpose is to trade while they hold it.
which is basically like trading in an imaginary item that may or may not exist - like the banking system does with derivatives etc.
anyways, there are a couple of hadith regarding hand to hand here:
Short selling:
Ibn Umar Narrated that the Prophet (May Allah bless him and grant him peace) said:
"He who buys foodstuff, should not sell it until he has received it."
(Sahih Muslim - 1526)
Malik son of 'Aus son of Al Hadathan reported:
"I was in need of change for 100 dinars (gold coins - denarius).
Talhah the son of 'Ubaidullah called me and we discussed the matter, and he agreed to change (my dinars).
He took the gold pieces and toppled them with his hands, and then said: "Wait until my servant comes."
'Umar the son of Khattab - May God be pleased with him (close companion of the Messenger of God -(PBUH))
who was present and was listening, said:
"By Allah! You either give him the silver, or give him back his gold.
The Messenger of God (May Allah bless him and grant him peace) said:
'Exchanging gold for silver is usury unless it is exchanged on the spot.
Exchanging wheat for wheat is usury unless it is exchanged on the spot.
Exchanging barley for barley is usury unless it is exchanged on the spot.
Exchanging dates for dates is usury unless it is exchanged on the spot.' "
(Bukhari 2174)
The problem with delayed selling was that some would manipulate it by for example agreeing to give gold, and saying that the amount in silver would be calculated according to the ratio with gold at the time of hajj- and paid then, when silver was more expensive at the time of hajj due to pilgrims bringing gold with them and needing to convert it to silver for daily use. It was a back door form of usury.
I'm sure that is not the intention in your case.
Though umar (ra)'s interpretation of the Hadith is strictly literal in order to avoid confusion.
Plus the fact that the buyer was preventing the seller of the silver from getting other offers in the time waiting though it was his right.
here's some info i put together a couple years back:
http://abz2000.com/TheMoneyChangers.aspx
btw, have you tried phoning your local pawn shops?
many of them source bars at around or less than internet price.