Does your account have a 2FA protection? Yobit will not gonna still 0.025BTC to it's user. Maybe your account got compromised. Scan your computer with anti virus. Maybe your computer got infected by a malware. Besides that, You can't prove that yobit itself do that transaction because it's obviously someone who compromise your account. The only thing you can do is track the transaction and if you are lucky. You can search the owner of the receiving address here.