Doesn't have error checking for invalid numbers.
Sent sms to a 20 digit made-up number and still said it was sent successfully.
Check out the following site (
http://www.cbfsms.com) for an example of how invalid numbers should be handled:
"SORRY
An Error Has Occurred
We are sorry, but access to what you requested could not be completed on this occasion. Details are included below. You may wish to return to CBFSMS.com and try again. Have you read the System Status? This service is run in accordance with the Terms and Conditions which must be read prior to use.
Invalid Number
Please check the number that you have entered, all UK mobile numbers start with 447 and are exactly 12 digits long.
CLICK HERE TO GO BACK"