It's true.
Remember when Elizabeth posted an image with Dawn's template?
Elizabeth said "I did it on accident" and Dawn said "I logged on to Elizabeth's account because I was bored." And later confirmed she did it on purpose. She stop replying after that. Blocking doesn't stop people from memechatting either and even if they stop following me I can still memechat them as we had previous messages. So she's obviously choosing not to reply.