Was recently hijacked by Reader DC Please help me get back

Hi,  I am looking everywhere to find my serial number. I was recently hijacked by Acrobat Reader DC. I can't tell you frustrating this is for me! I am a quadriplegic,  paralyzed from the neck down. I use a Tobii Dynavox which allows me to control my computer with my eyes to manage my day-to-day activities which involves a small home based business.  I use Acrobat Reader regularly for filling in text as well as converting PDF to Microsoft Word documents. Currently I was using it to fill out my W2 W3 forms. On my documents where I needed to fill I was able to choose the font and color of the font, and position them where I wanted them go. Acrobat Reader DC is much more tedious and laborious for me. All of my files were hijacked into a format that is vastly different. I've spent the better part of the last 2 days trying to get back the Acrobat Reader I had, and I'm not even sure what version it was. I just always updated when I was alerted. After all of my searching I understand I need a serial number to download a previous version. Could you help me find my serial number please? Needless to say, my eyes are tired.