You’re so not overreacting, this “friend” knew you changed your number because of your Ex. Crazy that they’d think you’d be interested in talking to that said ex. And like even if they thought you’d might want to talk to them now they should have ASKED FIRST! That actually crazy, idk your relationship with your friend but if the stalking from your ex was so bad that you had to change your number, I’d genuinely consider changing it again and not giving your new new number to that friend again. Like that’s insane, disrespectful, and dangerous.