Client Shop Bug

apon trying to purchase my last set of tier 3 runes i was given an error message reading that "you have attempted to purchase or already own more than the maximum amount of this item.". it is the greater seal of mana regeneration giving me this problem. when i first attempted to buy the runes i had 0 of them. After trying randomly every now and then i was able to buy up to 6 out of 9 but no luck getting passed the error message for the other 3. ive seen similar issues in other threads, please fix.