You can email them via their support email (on their website).
Or you can post on their ANN thread:
https://bitcointalk.org/index.php?topic=1972805.0Or send them a PM.
The Mistertango account is linked to this exchange:
http://btc-exchange.com/When you open a Mistertango account, you will be assigned a static bitcoin address. When you send bitcoins to the address, it will be converted to EUR based on the best possible sell rate shown on the exchange site above.
As for the fee, read through the ANN thread above. I found this post on that thread:
The fee is 0,5%, but no less than 0.005 BTC. Meaning, that you pay at least 0.005 if the transaction amount is less than 1 BTC.