Plug-In

Hello – I integrate the ads.txt file for infolinks onto my blog (manually, not using a plugin) but I cant find where I would have done so, as I now wish to remove it. When I search and tried to install the Simple-Ads-Txt Plugin (as I thought I’d be able to remove it) it said it is already installed…but it’s not on my PlugIn list!
Please help – I have now been accepted by Google AdSense which is the only one I wish to use. I just want to remove infolinks from my blog completely – and any other ad plug-ins and such too that are not AdSense!
Please help – Thank You!