HELP NOW

I just need to view my textbook that I purchased online.  I wasn't able to at first because my computer wasn't updated, so I updated my macbook laptop then downloaded the adobe digital editions as per the school website told me to do. After 2 days of finally figuring it out I had access to my textbook all week now today I go to go view it and it says my computer is not authorized to open my textbook because it's authorized to a Vendor ID.  I was never given a Vendor ID but put reset my password anyways, after doing so it says I'm not authorized still.  I just need to get my homework done already. please help me view my textbook.  Also would be more helpful if you just had a phone number I can help rather than having to navigate all through the website for help.