But they did make an announcement that they are suspending deposits and withdrawals on the 10th May. You are to blame for making a deposit on 14th even after the announcement, that why it wasn't credited
I have not enough idea about gate.io as I think I had only created an account on the gate.io But as a user of cryptocurrency I have opened account on multiple reputed exchange site as well as gambling site and everywhere I have seen option of withdraw/deposit is disable along with announcement. And if still not announced yet it is disables on the deposit/withdraw option. But on this site why they have not disabled the option of deposit.