Hello Mmkx,
Welcome to the community!
Firstly, you should note that Fido Roam is automatically enabled on Data, Talk & Text and Talk & Text plans. If you did not wish to use the feature, you would need to opt-out of Fido Roam. In doing so, your usage would be on a pay-per-use basis. It should mentioned that Basic plans do not allow for roaming usage.
~taken from here.
Fido Roam charges will only incur if your phone uses services -- make or receive a call, send a text message or use data abroad.
In addition, you should verify your device is compatible with the local providers in Cuba. There are various sites online (see here, here,.. etc).
Hope this helps 😀
Cheers
