Cancellation notice period

Saroj1
Level 2
I recently changed NBN provider and received an email from TPG that I will be charged for 30 days even though I won't be using TPG services as my service has been already transferred to new provider.
Is it a standard practice for all service providers needing 30 days notice even when the account is no longer in a contract?
It may be TPG policy but I find it unfair and will definitely deter me from considering TPG services in future.