Hello. I am looking to purchase/rent a sms gateway. Basically after a customer calls in I want to send them a SMS message. I looked at twilio/tropo but it seems you can't send a new message from their network. You can only reply to a message. The customer is OPTING in during the phone call so I want to skip the OPT IN message many providers use. I will also only be sending one message to each number. This is not spam. If you know of any services/people that can help me let me know. Thanks!