An order would be placed in one part of my app.
…then we package the order and send it to a 3rd party company for fulfilment. So I need to send a way of contacting the person if there are issues for the delivery.
Uber does call masking, so it is a relatively normal thing to do when you do have to use phone numbers.
Twilio and Telesign seem to be two services that could be used (and integrated into an app, fingers crossed).