Restrict reordering of products

-- Joomla version -- : 3.8
-- PHP version -- : 7

Dear All,

We wish to sell digital courses. One customer should be able to purchase the product/course only once.
If he/she tries to add the same product to the cart, it should not happen and should display a message.
How to achieve this ?
Any help in this regard would be highly appreciated.

Thanks and Regards

is there a way, that a customer could buy only once but still pick what ever quantity he need that one time? kinda like a limitation not on the quantity entered but on the product selection instead?