Hello,
Joomla debug mode is not the same thing that displaying PHP notices in the generated pages.
In Joomla you can see to override that PHP setting ; but best to let your web hosting dealing with that and not force the display of PHP messages, for your own safety.
Please don't hesitate to contact your web hosting for that and to perform some search on Internet to help you with the configuration of your Joomla website.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.