Hi Nadia,
This is OK but:
The word "pleased" should read "please"
Replacing the phrase
"...please leave...as soon as you" by
"...please vacate the internet access once you...
would avoid confusion with the gratuity of the service and is easier to read.
maybe you should prefer:
To remove the initial word "The" and put a capital at "internet"
"... and in the evening until ..." seems a better turn of phrase
"...other people..." could be replaced by "others"
Maybe ths phrase could read:
"If there are others, waiting on the sofas and the chairs, to use it..."
Sorry for nitpicking, since its otherwise very good english
Bises
Tantine