Blaupunkt windsor rcm 127 help

Hello, my father has a car with a blaupunkt windsor rcm 127 and the key card is lost. I ask, as a person that do not understand noting about it, help.
So, what is best course of action: disable the key card? If so, how? If it is better to get a new keycard, what to do? I already found a person selling 2nd blaupunk cards, but he says that one needs the first card, so I do not know what to do.
Thank you!