Hi Malbay, it sounds like you haven't bought the rest of the boxes within each stable - when you buy a stable you only get the use of one box, you then have to go through the collecting of construction items and getting a friend to work there again for each of the other three boxes in each stable.

Click on one of the stables and when it 'opens' you should see that it says '1 of 4 boxes' (or 2 of 8 for the main stables); at the top of this display box are two tabs - click on the right hand one to see the 'upgrade' screen where you ask for the help you need to construct the next box.

Irritating, I know, but the devs in this game seem to be going out of their way to make this game as difficult to play as they can - I sometimes think I'm only playing it myself out of sheer stubbornness and a refusal to be beaten!