Try to contact UNICREDit bank support maybe they can help you or at least give information about the transfer. I have account at Banca Transilvania and there is no hidden fees. Topped up 250 RON payed 250 RON. But if you will have any information please share with us.
You signed a contract with UniCredit for your card. Read it because the answer is there. Also you can check the Romanian thread to find out what other Romanian banks are doing the same.
I am a Garanti Bank user, but I had no fees at topup, can someone confirm if Garanti Romania has some fee at Revolut topup?