I requested a password change and never received any e-mail
Check your e-mail address and see if it is accessible and/or working (it may seem obvious, but always worth checking), and make sure MinerGate email did not get into Spam or Promotions folder.
If you’re absolutely sure that you have no traces of the message, please contact MinerGate support team and describe the situation.
You will be asked to provide some additional information about yourself and/or your account to verify you as the real owner of the account and to avoid any misunderstandings. This information can include some recent transactions (hashes, dates, amounts), actual balances on some currencies, maybe IP-addresses that you have recently logged in from. The more facts you provide, the better. You can even provide it in your original request, this will strongly expedite the process.
After all the info is on the table, MinerGate support will validate it and change your password manually to a random string. You will be provided with the new password and be able to log into your account and change it.