Faulty Uptime messages

Hi
I received a whole lot of 'Site Down' mesages last night (between 6 - 8pm AEDT) which cannot be correct as the sites were running on a mixture of different servers.
For example seedim.com.au is on a certain server, marmoset.com.au is on a different server, and the remainder of the messages concerned sites that were on our shared server (ie. bacchusmarshcp.com.au, reloadmarketing.com.au etc). The fact that site down messages came simultaneously means that your uptime monitoring is somehow faulty. Can you look into this for me please?
thanks