Without knowing the ins and out, just judging on what you say here...
You were annoyed about something she has done and rang her about it.
She has used attack as a defense and suddenly dredged up some wrong you have done to deflect from the bad thing she/they have done.
Clue- if they had have had an issue with your behaviour before, they'd probably have said something then.
This is just to quash your legitimate issue today.
You've backed down now about your issue, haven't you? That's what they wanted; to turn it all around and back on you.
Classic narc parenting. My mother would do this to me.
Denial of my concern/issue/complaint at her bad treatment of me
Minimisation of the same- because, after all, my feelings don't matter and I don't matter, only her.
Blame, well it was my fault because of xyz thing I did a year ago
Or as my mother said to me after I'd questioned her on why she moved home without telling me etc
"Well we were never that close"