is this site being hacked or is there an other problem?

Hi,

At this page: http://rejoycexpress.nl/contact
suddenly appeared at the bottom of the page this text:

bmw, audi, cadillac
audi, bmw, alfa

The owner of the site didn't put it there...

This is the html code of the text:

bmw, audi, cadillac
audi, bmw, alfa romeo

Is this site being hacked?
Or is there an other problem?

Do we have to take maesures to prevent this from happening?

We of course changed the inlog already.

We removed the text from the site.

Thanks in advance.

André