WhatsApp Banned My Account After Someone Else Logged In

My WhatsApp account linked to the number 73699517** has been banned for the last 6 days. On the screen it says that my account violates WhatsApp’s age requirement and it only allows me to register a new number. Before this happened, someone else logged into my WhatsApp account after I shared my WhatsApp details for login. After that, my account was banned and I lost access to my chats and contacts. I contacted WhatsApp support, but I did not receive a helpful or clear response and my access is still blocked. I request that my account be reviewed in detail, that the ban on my number 73699517** be removed if possible, and that my access to my WhatsApp account be restored. I also ask you to inform me clearly of the exact reason for this ban and what I should do to prevent this from happening again.