Russia has introduced a 20% value-added tax (VAT) for e-services and the VAT is applicable to e-services rendered by foreign suppliers to Russian customers. 

This update affects all of Adcash’s Russian advertisers that have their country set to Russia. The VAT is charged regardless of whether you’re purchasing advertisements for business or personal purposes. Adcash will deduct 20% of VAT from all payments, and this VAT could be claimed for recovery if general conditions for VAT recovery are met. Please contact your Russian tax authorities for further information.

How is the Russian VAT calculated? 
If you make a payment of 100$/€ on your account, then the actual balance transferred to your Adcash balance would be 100 minus the VAT, which is 100/ (1+20%) = 100/1,2 = 83.33 $/€

Note: Adcash can't provide tax advice, so please contact your country's tax authority for further guidance and help.