Ning.com Charged after the free trial Internet

I signed up for a free trial on Ning.com and looked around and decided it wasn't something I was ready to use.  So the same day, I deleted the sample page I created and cancelled my free trial.  I did this all the same day and never logged on to their site after this.  A month later I noticed a charge on my account from Ning for $300.  They charged me for a whole year of services without my consent or permission. 

When I contacted Ning.com they told me they never received a request for my cancellation.  I tried to resolve this without getting my bank involved and told them to look at all their records and they would discover that I deleted my page, cancelled the trial and never logged in again.  I was told they didn't receive my cancellation, and they didn't seem to care that I deleted the page and never logged in again as proof that I didn't use the free trial. 

I think it's ludicrous to be charged $300 for a service I never used and simply request a refund as the only means to resolve this dispute.