Hi @javid1360, we are sorry to know that you'd like to cancel the service. Please send us a private message with your TPG customer ID, username and complete address so we can pull up the account and assist with your concern.
To send a PM, please refer to this link: How do I private message (PM) in the community
Cancelling your NBN plan is typically a case of calling up your telco or hitting them up through their live chat, although options will vary from provider to provider. A phone call tends to be the simplest option, and for the most part, you'll never be able to cancel an NBN plan through an online portal.