My Plaza setting?please help urgent

[unramped]

Hello all,
          i am having a problem here with myplaza that when any user even me with admin login try to buy an item i have created on my site like(Hosting plans) its does allow to do and gives an error.

Quote: You cannot buy this item as you already own more of this item(or type of item) than you are allowed to carry.

how resolve this issue?

mu forum url is http://www.unramped.com/