Confirm the action. This will remove any contact information that Telegram previously uploaded from your device's address book from its servers.
What this does: This effectively "resets" Telegram's knowledge of your phone's address book. Any contact you haven't explicitly added or chatted with before will no longer automatically appear, even if they are in your phone's contacts.
3. Blocking a User (For Complete Disengagement)
If you want to prevent someone from messaging you, seeing your online status, or adding you to groups, you need to block them.
How to Block:
Open the chat with the person you want to block, or find them in your Telegram contact list.
Tap on their profile picture/name at the top of the chat to open their profile.
Tap the three-dot menu (⋮) (on Android/Desktop) or "Block User" (on iOS, usually visible directly or after tapping "More").
Confirm the action.
They can no longer send you messages or calls.
They cannot see your "Last Seen" status or if you telegram number database are online.
They cannot see updates to your profile picture.
They cannot add you to groups.
Note: Blocking does not delete previous chat history, but new messages from them will not reach you. They will not be notified that you've blocked them.
4. Deleting Chat History (If you want to remove the conversation)
Deleting a contact only removes them from your contact list. If you want to remove the conversation itself.