My hosting provider aren't really being that helpful. I have asked for the logs but been told these are for internal use only. Since I am on a shared server, do you think perhaps that this issue may have been caused by another website on the same hosting machine and they are just not telling me? or do shared hosts not work like that?
I already use Captcha on my contact page and so I may investigate some of the other email solutions you've suggested. Are there any companies that you can recommend? A quick search brought up SocketLabs but I need to do my homework.
Thanks ever so much for taking the time to give such a detailed reply, when it clearly isn't a WebAssist issue. Your technical support, is always incredible – Thanks Ray.