14 grace period applies for all contracts etc, It applies the board, from phone contracts, to car finance, and mortgages.
It's a legal right, it over rules company policies. Some companies may make it difficult but any financial commitment comes with a 14 day grace period.
I don't know how you got it so wrong, there has never been a legal right of cancellation for signing a contract or buying an item in a store and and then changing your mind.