Ist clickatell.com sicher?

A good SMS provider only to GSM number in Indonesia. BUT a big BUT here, required you to send a credit card statement for a fraud screening. A once-off procedure that is a hassle to begin with and asking for an internal private data of our company. I have to contact my boss, print the letter of consent, ask for my boss signature, and a lot more works to be done and accomplished just to refill my office account just to realize that a credit card statement is out of question. How can I trust them if they even can't trust their own legit customer who have paid before ? Why can't they just do the verification based on the registered phone number at the credit card issuer rather than asking for an internal document that my boss protect like hell. Even a Singapore Apple Store can do it, so why can't they ?