if I've created account/wallet on coinbase or any other exchange then my account is hacked and my coins/money lost who are responsible for it
The Exchange where I've created account

is it my mistake

what's you thought about it

and how i make my account safe

Hacking and cracking of data happens almost on daily basis. This normally disturb thousands of users and involves great loss. And all depends on both ends, user and exchange ends. We should not blame others by layering up ourselves mistakes until and unless guarantee comes on others errors. So its better to verify all the possible ways from which end actually fault occurred.