If you block a contact on Telegram, you no longer receive messages from him. But if you delete a contact, you still receive messages but you won't see him in your contact list. To delete a contact on Telegram and remove him from your contacts list, do as follows:
1. Open the Telegram application on your Android device
2. Go to your Contacts and tap the contact's name you would like to delete
3. Now, the conversation page opens and you need to tap the contact's name on the top
4. The contact's details page should be opened. And all you need to do to remove that contact from your list, is to tap the 3 dot icon on the top right and then tap the Delete option
5. Confirm and you successfully deleted a contact on Telegram for Android.
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