I live in Madrid near Plaza Mayor... what is the closest pickup point for rental of one of your cars?
The closest places are around Gran Via and Atocha Train Station (where they are open longer hours and even on the weekend)
I recommend you do a search on a laptop or tablet so the available cars will be displayed on a map for you to be able to see the nearest locations to you with available cars based on your search criteria.
Can you give me the exact address
I can't, sorry, as the available addresses depend on your dates and times.