I agree - give a deadline and then follow through 
on it- I would say a week- and if you don't have 
your money or the cels, start filing complaints.  
The person may never have had ANY of the cels, if 
you can get a shipping number for the other 4 you 
might let him keep the balance for those, but 
make sure you get a refund for the 5th cel, and 
again, make sure it all happens within the time 
frame you specify.