How to get a client to pay

Hi,

I've just completed a large CGI application using Perl.  I took 50% when I 
started but now that it is complete and installed on their server they have 
not paid the final 50% according to the contract.

I've e-mailed, faxed and phoned but with no response on their part.

I"m from Toronto/Canada and they are from Las Vegas/Nevada.

Has anyone had this experience and what recourse do we have.

In short how do we get the client to pay.

Thank-you

David Jourard
Bytes Interactive 

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