4.I cannot add more than one item to cart

This is usually caused by your php sessions not being set-up correctly.

In 99.99% of cases this is due to the session save path (php.ini) not being set correctly or at all and/or the directory not existing or not being writable.

Typically this would read
session.save_path = "/tmp"
session.save_path = "/var/lib/php5"
session.save_path = "/var/lib/php5/session"
or similar in your php.ini.

Refer to the php manual for more details regarding session setup

You should speak to your host / server administrator to get this fixed and to make sure the appropriate path is set with the correct permissions. WPPizza will not work without php session support.

Suggest Edit

documentor id 7