Q: why can't i buy coins for games

What happens when you try - as these are user-to-user forums we don't know what you see. If you are getting a message to contact iTunes support then you can do so via this page : http://www.apple.com/support/itunes/contact/ - click on Contact iTunes Store Support on the right-hand side of the page

If you getting a different message or something else happens ... ?

I have been trying to buy coins for Jackpot party for 2 0r 3 days and they send me here every time and say something is wrong with a game I purchased.  I don't know what thhey are talking about.  Can I buy coins from some where besides iTunes?

This support stinks.  You can never get an answer.

If you are getting a message to contact iTunes Support then have you done so (these are user-to-user forums) ? If you haven't contacted them then read my above post for the answer on how to do so.