After Plugin deinstallation, Login impossible and line50 error

If you have access to your cpanel, or equivalent in your hosting, you can disable the plugin manually.

Go to file manager, find your root folder, ususaly under public, public_html or www, something like that.

Now go to wp-content -> plugins -> plugin folder, im guessing the plugin folder will be named coming-soon or something similar.

Rename the plugin folder to something else, coming-soon1 or whatever.

This will disable it and, most likely if not other error occur, you will be able to see your site and login without problems.