Is it normal for your parents / grandparents to stop contact wih you?

Not really, unless there's just something really wrong with them or there's been some kind of fight or something

It depends on the situation- if there has been arguments or some provoked deliberate cause then they may feel its morally correct to stop contact however if they have done it unprovoked and without a cause then its unjust and horrible for you to go through.

This could be a very difficult family situation. And one that may have absolutely nothing to do with you. There could be issues and concerns there that you are unaware of. Perhaps sitting down and speaking as a family with your parents or guardians can help you to better understand or to find the answers that you seek.

We are all born into different situations, different ways of living. In a "perfect society" no, they wouldn't stop contact with you, but we don't live in a perfect society. Understand that life is always changing and so are all who live in it. If for some reason someone feels neglected by a loved one, first do not assume it is because of you for any reason. Talk with them and see how there life is going, you may be surprised by their answers.

It depends on your definition of normal and the circumstances. Long time ago it may have been frowned upon, but today it is common. I was raised a Jehovah's Witness and if you stopped being one it was normal and expected that you be shunned (no contact wtih you) by all your family and friends who were still active members. And many times that included your parents and grandparents.

It's normal for your parents and grandparents to stop contacting you because they are wanting to see you be more independent to make your own choices or even saw you becoming way to dependent on them helping you that they just want to give you some space now so you can learn to help yourself.

Unfortunately, and as upsetting as it is things like that happen. We cannot control other people (even family) behavior. Though we can make the effort to understand.