MAC Mini with No OSX Installed

Hi,

I have recently purchase a second hand MAC Mini 2010 model which has had OSX wiped and returned to an new state.

No OSX disc was available but I was told that I could go into the recovery mode and re-install OSX. I have tried this but keep getting an error code that the service is unavailable please try later.

The version its trying to install is OSX Lion 10.7, can I purchase a disc and run from boot up?

I have an IPAD and IPHONE but I am unfamiliar with MAC desktops

Thanks

Ricky