Official contact route for MetaQuotes-Demo XAUUSD commission tariff

 
Hello, I use an MT5 demo account on MetaQuotes-Demo with USD currency and XAUUSD (shown as “XAUUSD, Gold vs US Dollar”), terminal build 6207. Could a MetaQuotes staff or administrator identify the provider or account owner responsible for this demo server and the official contact route for requesting a dated XAUUSD commission tariff, or written confirmation that one is unavailable? I understand that forum replies are not an official tariff. Thank you.
 
MetaQuotes-Demo server is mostly used to update Metatrader to the beta builds and to test beta builds of Metatrader, and it (demo account) may be provided for limited time only based on inactivity or any.

And the servers/accounts with the brokers should be used in any other cases/situations.