I think you have every right to send at least 
one e-mail a week to the seller. That way you can 
constantly remind him/her that you are still 
waiting for your cel. I always encourage anyone 
that buys from me to keep in contact on a regular 
basis at least until they receive their cel(s). 
Naturally, if the person you are trying to 
contact tells you that you are bugging them then 
of course lay off, otherwise e-mail away ^_^

 -Cel Addict