Answer 1

Kindly use search bar
https://www.sololearn.com/Discuss/2397557/?ref=app
https://www.sololearn.com/Discuss/2529388/?ref=app
https://www.sololearn.com/Discuss/2579718/?ref=app
https://www.sololearn.com/Discuss/2595394/?ref=app

Answer 2

Visit the profile whom you want to send message, click on the three dots on top-right corner, choose send message.
You message will be sent to receiver, if he/she accepts the invite to start chatting, then only you can message them again.
Also, you need to have your account verified. So visit sololearn settings, and there it will be present to activate ur account.
Hope this helps.
also, if you find anyone's answer to your question helpful, mark them as accepted, as it motivates others, and helps other visitors to find the answer.

Answer 3

Complain about it I guess.