Hey!
What is the best place to do this?
I have steal for over 1000 gold and the quest want not update, is it bugged

Pick pocket people usually works, our break into a store at night and grab stuff off the shelves. Remember it's 500 gold worth of goods, not just gold.

The Jeweler's cart by the main door has some pricey items. It's a bit tricky to get to since you can't crouch/sneak and get to it though.

Try this, best method with stealing goods from cities.
Go to alchemy shop, steal a expensive potion, drop it, steal again, drop it, steal again.... done
example: let's say a potion costs 100, steal it, drop it - repeat 5 times

Gold itself doesn't count, it has to be items.

Not true. Gold in containers marked stolen certainly counts.

I've found the best way to do this is to avoid people's houses and go right for businesses... the jeweler's cart, the temple of diabella, the hag's alchemy shop. The general goods vendor right at the gate isn't so good, she hasn't got much.

Avoid the dwemer stuff and Calcimo's stuff, none of it seems to count. I also can't get enough out of the Silver Blood Inn to make it worth the sneaking and watching for the innkeep's wife.

Don't get greedy... at the jeweler's cart she has almost three full trips of stuff and to rebuild the guild you'll need to hit 5 marks in each city before you can do the radiant questline... take only what you need and there will be more to come back for.

I went to the guard barracks and took a sword, helm and shield and that triggered the 500 coin limit.

Dont give up. I thought I wasnt anywhere close, and stealing 20 gp items would take forever. I think that maybe the items count for more than the display value though because I reached the count when I thought I was still far off.

I've found the easiest way to do the bedlam jobs is to try to get a sweep job from Vex in the same city. The 3 items she asks you to steal are almost always enough to cover the 500 gold worth Delvin wants.