In addition, it is also interesting to analyze the channels your users are coming from. How do different marketing campaigns perform regarding user numbers and submission of contact information? Does your Google Ad campaign perform as well as your Facebook campaign? You can dig into these benchmarks under the Benchmark tab within your Audience tab.
You might want to take the channels visualization as a starting point when assessing the quality of your different channels. It is suggested to look into the other metrics first before thinking that your Facebook campaign is underperforming and then deleting it. Within the previously mentioned 'All Pages' tab, you can cluster how users from your Facebook campaign behave. Use your demographics and interests to see if the right people are targeted through your Facebook campaign and if not, adapt your Facebook marketing campaign first. Before doing so, you need to create a custom audience group.