When we make a choice and communicate that clearly to those around us, it’s far less stressful for everyone involved.
If you don’t want someone to pass calls through to you, then say:
“I’m not taking calls until mid-day”, rather than “I can’t take any calls now”.
If you are invited to meet with your account manager at xyz company because he’s “in the area” but it’s not something you want to do, then be honest about why. “I appreciate the invite, but I don’t take in-person meetings unless you are a potential client”, rather than “I’m sorry, I’m busy this week and can’t meet”.
I rarely take marketing calls, but if I happen to pick up the phone when someone does call, I politely decline their invitation. “I’m sorry that’s not something I’m interested in”. If the caller presses to send me an email outlining their product as opposed to meeting in person, I say, “I appreciate you have a job to do, but don’t send me an email. I will just delete it any way.”
Being direct doesn’t mean you have to be rude, and it makes for much clearer communication.