What a funy story, coins of gold, old women and shop keeper

Jamila Asif was once an old woman who needed to clean the loft of her house.  So she went upstairs and started sweeping the floor.  She found ten gold coins there! She was very surprised and happy.  I must go and tell all my neighbors.  He said.  So she kept the gold coins in the kitchen and ran out to tell her friends.  She went to the well, where the women of the village were filling water and talking.  Hear me! She shouted, I have found treasure in my loft! What do you think about it?  Good, every girl said this is your luck.  You must keep them safe.  Because there is a fear of this treasure being stolen.  By the way, where did you put them?  Oh, I left them in the kitchen.  (Continued) said the old woman.  This is your stupidity! Her friends said, come with us, we will show you a box in the village shop.  You should buy it so that you can keep your gold coins in it.  So she went to the village shop and saw the box.  I should take it.  He said, this will keep my gold coins safe.  But thieves can easily take this box. Said the shopkeeper.  Look, put your coins in this box and buy a big and strong box from me and put the small box in it.  Thieves can't easily carry something so big and strong.  What do you think of this box? It's the strongest I have.  The shopkeeper said, pointing to the big box.  This is a great box. Said the foolish old woman.  I should take it.  I am sure no thief can take it.  I can barely lift a corner of it myself.  My treasure will be perfectly safe.  Do you have a key to lock your house?  Her friends asked.  If you do not lock your house, two men can easily come and take it in your absence.  Wouldn't it be better to get a new lock and key for your home?  Then you and your wealth will be completely safe.  I have a strong new lock key.  Said the cunning shopkeeper and showed him a shiny new lock.  When it is on your door, no thief will be able to enter.  I must get this lock and key.  Said that fool.  Now surely my treasure will be completely safe.  I bring all these things to your house now.  So he and his boy brought all those things, said the shopkeeper.  After reaching home, the shopkeeper locked the house and demanded money.  Two gold coins are the cost of the box and ten gold coins for the big strong box and two coins for the lock and key, so you pay me for that.  The shopkeeper asked for the price of the box.  The foolish woman gave him the coins and he left.  Then he thought that he should put his treasure in the chest and the chest in the big chest where it would be safe.  But he could not find a single coin to put in it.  Can you tell where his coins went?