I get that I made the mistake but they should not have even accepted the deposit if it did not meet their minimum. I feel like I was robbed.
Who told you to send them more.money to reached the minimum? You told us that you are getting automated emails from Bittrex. If by Bittrex then just do it. If by user who have the same experienced, then just do it. If by speculation, then just try it but deposit minimum and see if there will +10usd that will be added.
If you aren't sure then no choice but to wait for Bittrex respond.