From Minergate's Terms of Service:

" Minergate.com is not a wallet or custody or any financial institution in any aspect. Pool operator is not responsible for any loss of caused by any reason while working with the pool. Cryptocurrencies carry a high level of risk, any kind of losses caused by the third party activities has to be handled by the user.

Once coins have been sent from the pool it is up to each user to track their coins and ensure payment details are correct on the site. Transactions can not be undone by the pool."

So yeah, say goodbye to your money...