A two word reply comes to mind. It's something like "Fu(k off" !
I don't know what kind of phone you have, but on mine, I have a block feature. I love it. It is the best feature on my phone.
On my phone, I go to the number that I want to block, and go to options, and down near the bottom of the list it says add to reject list. I can block up to 25 numbers.
Maybe they are upset with you.
passive-aggression? well, it is friday...