Hope you're generally doing well, Tigger.
We don't ever advising faking sexual responses. It gives partners the wrong information about what you like or what works for you, it's dishonest, and it also makes your sexual life into a show or performance rather than a real, shared experience.
I would suggest you have the same kind of talk with them you are having with us here. And if you did not tell them you were not okay with what you mentioned above at this time, you for sure need to do that, and in the future, do that at the time, ideally. You can let them know that when they do things like answer a phone during sexual activity, or start talking about random things, you feel like they're bored and also don't like how they don't seem to be all-in when it comes to having sex with you. You can tell them those things have bothered you and have you concerned that they don't actually want to be there. You can let them know that you feel like their words and their behaviours don't seem to match up for you (they say they're into it, but they are acting very distracted). Then I would ask to talk about this and ask them to be honest, even if being honest might suck or feel uncomfortable.
If they say they really are all there and into things, then it might just be a matter of asking for some simple changes, like them turning their ringer off and choosing not to start talking about random things in the middle of everything because now they know you don't like that.