She had sent the message while in the elevator, where there was no signal, so the message failed to send, and Atra Blanc never received her text!
Later in the Japanese restaurant, the cellphone signal was poor, and even if Atra Blanc tried to call her, she couldn't get through. No wonder Alexander Summers came looking for her in person—he must have been unable to reach her and was worried something had happened to her.
Upon realizing the cause and effect, Purple Summers looked up at Alexander Summers again, feeling not only timid but also a bit guilty…
She hesitated, but eventually spoke up, "I'm sorry, I didn't notice my phone had no signal. Is Mom really worried?"
"Mhm," Alexander Summers replied indifferently, betraying no emotion, "She made a whole table of dishes, waiting for you."
Purple Summers felt the inexplicable sense of trepidation in her heart grow stronger.
Alexander Summers was clearly angry, and moreover, he was angry with her.