I'm not a fan of any of them but I don't see this is being particularly egregious to me. But if it is that egregious to you, go tell them they suck and fight with them. I mean from the outside -at least one observation -is it isn't the fact that they texted or even that you lost a minute or two – it's that it erupted the illusion that for that period of time you're the only person that exists for the therapist - which I'm not saying if that's something that you care about isn't going to be a jarring experience -But try yelling about it in the minute that it happens. See how it goes and see how the therapist responds. It might not be how you want it or you might be able to come to an agreement that the therapist won't text in the middle of your appointments