appointment +

I tried to activate nari.org.in but have following error:

Fatal error: Class 'Google_Signer' not found in /home/content/15/10305915/html/nari.org.in/wp-content/plugins/appointments/includes/gcal/auth/Google_P12Signer.php on line 26

I just deleted plugin from FTP.

what to do with this problem.

Jay