I got a cell phone with pre-loaded SIM card for US from Clay Telecom through my office. On reaching US, when I turned ON the cell phone, it said Invalid SIM. I tried every setting possible, including inserting the SIM into my quad band HTC Explorer.
The error was consistent - Invalid SIM. When I some how contacted the company, the said they will try to send a new SIM to my US address within 24hrs. However, they never delivered anything, it was just a dreamy promise.
They neither have the capability nor the know how to operate overseas network communication. They should rather retire and let other proficient, competent organisations to provide the service. They are no good, avoid Clay Telecom.