Plugin CSS being overridden

I have installed and uninstalled 2 different contact form plugins (not at the same time) yet I cannot get the styling of the plugin to show. It seems to be dominated by the WP theme CSS. The page in question is located here http://texomafcu.com/contact-us/. I have tried to modify the plugin CSS but this doesn’t work either. As you can see, the fields aren’t visible because there are no borders and the backgrounds are the same color as the page background. I have tried to modify the plugin CSS both through the WP editor, and also locally on my machine and then uploading it back to the proper directly through ftp.

I have run out of options as how to keep the main CSS from overriding the plugin styling. I have also tried modifying the main CSS as well but haven’t had any better luck with that either.

Any suggestions would be welcomed. Many thanks in advance!