Messaging windows, in plain language
Messenger, Instagram and WhatsApp only allow a business to message a person within 24 hours of that person's last message. Toong respects this: older contacts are excluded automatically, so you can never accidentally message someone you are not allowed to. Telegram has no such window, but it still only lets you message people who started a chat with you. Email has no window at all, because replying to a month old thread is normal.