I don't know why someone has your phrase. And what is the condition of the people after owning it. But what is certain is that it is quite risky to let other people know about such an important thing. So, if it's already happened, it's better to create a new wallet and send the coins in the old wallet to the new wallet. So at least this can first secure the coins you have. Even if only a little. However, also consider the number of coins and since when the promotion was carried out.