forgetting, for getting

Forgetting or forgetting ( one word ) is a participle ( used with a helper verb ) of "forget", meaning to fail to remember; to be unable to recall--
Are you sure we aren't forgetting something?
Stop him; he is forgetting his package.

Forgetting may also be a gerund ( an action word used as an idea or thing ), meaning the inability to remember; failing to recall--
He has a habit of forgetting the time.
Forgetting is easy; remembering is difficult.

For getting or for getting  ( two words ) means in exchange for or in consideration of ( for ) obtaining or acquiring ( getting )--
How much should we tip him for getting the luggage?
For getting may also mean used for the purpose of ( for ) moving or causing ( getting )--
The ramp is for getting on the bus.

Now that you knowm that, you can say--
"You're forgetting that the bell is for getting our attention."