No one will buy the writs, so you can just drop them where you like. I've never had real problems when I had more than one writ on hand... sometimes Signore Pastolio would do the old in and out, and sometimes he would just let me go where I wanted.
There is another option to get out of the "I'm lettin' you in now... I'm lettin' you out now..." trap. Whenever he lets you go where you want, run through the door as soon as it opens. He can only transport you between the maps if you're actually in that room. If you run out and he closes the doors... nothing happens. And he doesn't even close the doors! Just start through as soon as he starts talking again.
With respect to the pick axe, you may be falling into some confusion. A pick axe lets you "open" an ore pile by using it on the pile. An ore pile has a chance to either give you something or be empty. If it's empty, you can get the "something is needed" message (I think).
If it gives you something, that something is a gem. Clicking on the gem will add it to your inventory. Gems are nice to sell...
In two spots in the game, an ore pile will yield a silvery metal. That's the Dragon Ore that Freyedies is looking for. Give that to him, run back to the entrance to the lower mine shafts, and run back to him, and he'll be done with your dragon armor. You can then steal it back from him, give it back again, and repeat the process.