will getting the code work?

i had to take the battery off my renault laguna, so now i need the code which i dont have, on the radio there are 2 lebels from a company for de-coding, so it seems the previous owner had the same problem. what i need to know is if i pay to get the code will the original one still work seeing as it has been de-coded before or not. can any one help and advise me what is the best thing to do to get the radio working again.