Refreshing delay

[F GV]

Hi,

Yesterday at 21:00 hrs (now is 15:00) i changed zone
files to adecuate them to my new ip address. (I
changed my ISP).

Today, some ISP servers in my country do not refresh
yet that changes. So i have the next questions:
Why this happens? 
What do i have to do to finish refreshing?
Do i have to reduce the TTL?

Thanks in advanced.

__________________________________________________
Correo Yahoo!
Espacio para todos tus mensajes, antivirus y antispam ¡gratis! 
Regístrate ya - http://correo.yahoo.com.mx/