Yes, you can cancel or deactivate your Smart Refills subscription at any time.
In the Mitte App navigate to the "Cartridge & Cylinder" tab and onto your Smart Refills status at the bottom of the screen.
Tap "Edit" and at the bottom, you have the option of deactivating Smart Refills. It is also possible to pause and cancel just your Mitte Home cylinder or cartridge independently.
Afterwards you have the option of also cancelling your subscriprion.