Silver Invest Applied Currency Difference Despite Fixed Exchange Rate Campaign

I started investing with Silver Invest. The money I invested benefited from a fixed exchange rate campaign. Now that I made a withdrawal, there is a currency difference in the amount I received. When I logged in, the fixed exchange rate was shown, and it should have been the same when withdrawing. I was supposed to wait for a month, but I need the money now. How can I wait in this situation? This has discouraged me from investing. Please resolve my issue.