Hello,
I am also having the same issue of a cart with thousands of items that were created months ago. I have tried the settings above (cart retaining period 3 days, frequency of checking carts 1 minute) but it doesn't work. Only when I save the configuration, 50 records are deleted from the cart, but then it is stuck there. Every time I save the settings, 50 other records are deleted. But none are deleted automatically as it is supposed to do.
As a more general request, I really wish it were possible to have a lighter Hikashop. No extension bloats my website and database like it. Thousands of records that get stuck in a cart, thousands of zones, dozens of shipping plugins, nearly 200 DB tables... it would be nice to be able to set some of these as options upon install for those who wish to have a lighter and less cumbersome component.
Thank you, and wishing you a happy new year!