1998 Mercedes Benz C180 radio code

After changing battery car, I had to restart my radio by writing a code. I tried few code that I find on internet but nothing worked. And after all this I opened the mercedes guide which was always in my car but never use it cause it is in german. In that guide I found the right code but till now could do nothing. It always says wait and I wait for hours but the radio does not work. Pls can u help me to make it work again? Thank you