So curently TakePOS works with Products only
I hacked into the files and figure how to make it work with Services
go to your root folder and look for takepos/takepos.php
and on line 88 fild the code
//$conf->global->TAKEPOS_ROOT_CATEGORY_ID=0;
and comment it out like this ’
$conf->global->TAKEPOS_ROOT_CATEGORY_ID=0;
Please note that this is changes to the core files and will be removed upon updates.