When you send large quantities of SMS, it is just like email from a filtering standpoint. You need to make sure you have different numbers to send from, that you spread the volume out, and that you modify the text of your messages to not give the filters a pattern to work with to filter your messages out. If you do that, you will get good deliverability, open and conversion. And make sure to actually opt people out when they ask to be opted out, or you will bring wrath down upon yourself from the carriers through your supplier and to you. Message me if interested to learn how to accomplish all of this at prices below Amazon's rates (as long as you are doing large volumes)