I get very triggered by unknown numbers as well, even though logically I know there isn't anything to fear but my PTSD goes nuts regardless. Everytime I have had it happen, it has been a telemarketer or some sort of sales pitch for insurance. When I start to panic about it I try and talk about it with someone so they can help me rationalize it, or I remember my grounding exercises to help me through my panic and I am very gentle with myself for the next few days because I know my anxiety and startle response is going to be high. Do you have a therapist you can discuss this with? Or why this triggers you so bad? Sometimes getting to the root of a trigger helps defuse its power. Sending peaceful thoughts, Typo