If the application can't be removed, then I suggest you to take a different approach. These applications are used to track the connections, GPS info or your phone. It could be a major issue because you are exposed to public users. If someone installed it, then the first thing to do is to go to Settings > Security > Device Administrators. Disable the application or disable all the applications from that list then attempt a new uninstall operation. It should work afterwards.
On a side note, always install apps from the official Play Store.