Termination of a Telegram account is irreversible. If you sign up again, you will appear as a new user and will not get your history, contacts or groups back. People, who have your phone number in their contacts, will be notified. The new user will be displayed as a separate conversation in their messages list and their conversation history with this new user will be empty.
Telegram is not a commercial organization, and we value our disk space greatly. If you stop using Telegram and don't come online for at least six months, your account will be deleted along with all messages, media, contacts and every other piece of data you store in the Telegram cloud. You can change the exact period after which your inactive account will self-destruct in Settings.
+You can delete most of your data without deleting your Telegram account.
+To delete individual messages or entire chats for both parties at any time, simply tap on a message (or hold to select any number of chats) and tap on the delete icon, then check the option to delete for both parties.
+Many relevant settings are available in Settings > Privacy & Security (on iOS, there is one more step > Data Settings), for example:
+For other data:
+First of all, sorry about your phone. Unfortunately, the phone number is the only way for us to identify a Telegram user at the moment. We don't collect additional information about you, so whoever has the number, has the account. This means we can't help you unless you have access either to the phone number or to Telegram itself on any of your devices.