Cant purchase with Ip

Guys i have been trying to change my name for the past few days and i have 14k IP. and whenver i try to purchase a name change it wont let me. I have checked the name if its available like 10 times already however it still not letting me. It tells me that i do not have enough IP. Its telling me i only have 13.8k IP but i have 14.5k IP please help