What should an employee do if a customer calls asking about Vodafone Live ringtones that resemble songs, knowing their impermissibility, and being bound by company policies that prevent him from informing the customer of that?

If the ringtones provided by your company to its customers are ordinary tones, then there is no harm in your work. However, if they are ringtones with music and song melodies, they are forbidden, and it is not permissible for you to work on providing them. You should seek work that does not involve this forbidden element.