Youβre asking the right questions, at some point we must ask @Shoprite_SA why do they hire cashiers and also force them to do the cleaning and packing after work with all the profits. Why not hire a cleaner dedicated to cleaning while creating employment.
You should have deducted R5 just to teach her about tax. Give her R15 then at the end of the year send her a letter she owes you R10 for not submitting her tax return on time. Plus a penalty for late submission.