TeamViewer Sent bill to collectors after I cancelled Service.

I tried to download the free non-commercial version of Team Viewer.  Instead I somehow ordered 2 professional versions for about $500 a piece, no I am not good with computers.  I was told I could call and cancel and get the issue rectified.  I called and cancelled, and then got another email saying I still owed money.  I called again to cancel and this time a month or so later I get a phone call form a really rude lawyer saying I owe over a thousand dollars.  When I said I had cancelled I was told I didn't send in anything in WRITING.  I spoke with them twice about this.  Keep in mind I only needed the free version of the software for a day.  The Lawyer then said he was going to talk to team viewer.  He called me back today, again as rude as can be, and said they where only gonna charge me for one license.  I don't have a license, have not used a license, so I'm sure not going to pay for something I don't have and called twice on to rectify the confusion.