If it’s low effort just keep sending in invoices. You could even write a script to help. The data entry person puts them on an A/R which gets larger and larger as each payment is not made and the past due rolls to the next invoice. Eventually the over 90 A/R will get attention.

It’s a lot of effort to keep going so it may just be more hassle than it’s worth. On the other hand, nothing wrong with that process if you’re within the terms of the contract. When the number gets large enough it will get escalated and, when you show your work, get paid and the payment clerk will get their hand slapped.

I mean they will pay them if you escalate to legal but you won’t be able to do business with them again.

You'd think "suspend service until outstanding invoices are paid in full" would be in the "things which you would/can do about it" category.

Sometimes, they'll go as far as stiffing your payment just because.. what are you going to due, sue a Global 100 entity?

It's absurd, that's why I like working with smaller companies.

That's what credit reporting agencies like Dun and Bradstreet are for.