1. Well, verbal/poral partition is as good as partition by way of proper deed pf partition but the same is of course subject to proof and is why people choose for written partition deed so future complications can be avoided.
2. I am not sure whether you are currently enjoying more share that what you are entitled to,
3. If not then you can not be deprived of your due share.
4. If you are getting hindrance to enjoyment of your due share then you can file a suit for partition and injunction to lay claim of your due share and separate possession.