Welcome the Technical Support section. Help us in assisting you by providing us with a concise and descriptive elaboration of your issues. Be specific and if possible, provide us with a step-by-step instruction in replicating your problem.
we have the setting at jomsocial backend > configuration > site, Number of displayed comments at wall section
I cant login to your site, but Show previous comments is there?
that issue from 3rd party template. if you switch the template to protostar, Show previous comments is there:
please goto jomsocial backend > configurations > templates, and make sure Jomsocial as selected/default template.
and please have a look at joomla site template, if you found this location:
/templates/gk_portfolio/html/com_community/
please remove or rename com_community to other name.