API REST Expert Needed

This is a project that a coder started but never finished. It's 90% done, I just need someone to finish it up. We use multiple [login to view URL] "Pro" accounts to manage the client databases and marketing campaigns for several clients. Sendpepper sends emails, but it does not send text messages. So we setup an API bridge between Sendpepper and [login to view URL] to send text messages. When a person opts-in to receive text messages through Sendpepper, it successfully sends a confirmation message from Optit and puts the client into their [[login to view URL]][1] account. Our clients should be able to login to their own account at [[login to view URL]][1] and all of their clients who have opted in to receive text messages through Sendpepper should be in there. But when you try to send a text message from [[login to view URL]][1] , it doesn't work, and the guy who originally set it all up has disappeared. Please help!