Can you give us some more information as to why the gimbal does not work?
Have you crashed the Anafi?
Does the gimbal not move at all?
Does the gimbal not initialise correctly?
Spare parts do not seem to be available from Parrot direct so you will be looking at buying a second hand gimbal. Even if you manage to fit the replacement there is no guarantee that it will work as it appears that the gimbal ID is hard coded in the Anafi firmware. If you search this forum you will find many threads regarding gimbal faults are the suggested solutions.