"Harasser returns--what is this behavior and why?" Because harasser, bullies, abusers don't want to be seen as such - they operate by turning it around so that *they* are the victims. One should not indulge and/or enable this behaviour

Your daughter really should block these girls/numbers and not have anything to do with them i.e. no conversation, no apologies. Otherwise, it's merely feeding these people and giving them what they want.