Some Facebook advertisers prefer to not pause their ads. Instead they set the daily budgets to a value less than what was already spent, therefore the ad sets stop the delivery without changing the status to paused. Here is an example:

See, the rule would set the budget to $1 when an ad set spends half of the daily budget given that the ROAS is not high enough.

Then the next day you can have another rule revert the budgets to normal. It may go like this:

Set budget to $X if
Daily budget <= $1 AND
Spend > $1 (yesterday).

If you have different tiers of budgets there is a way to make it work, you'll just have to rename your ad sets in a certain way and create a rule for each tier. I'll be happy to help, please don't hesitate to ask any questions on intercom or send them to help@bir.ch.

Cheers!