if the contract your client signed said net-30 then wouldn't a 90 day payment incur 60 days of late fees and another invoice? i feel like you could rinse/repeat that forever. It would be like a subscription to late fees.
If a customer is paying you late because they think you won't/can't do anything about it, it seems the same disregard could apply to their payment of late fees.
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.
They usually just reject the invoice with late fees and quote their stated 90 day policy. Also usually they will redline it if you try to put net-30 and just change it to net-90 anyway.
It's up to you if you accept 90 days in a contract or not. And if you accept 90, then it's absolutely within their right to wait until day 90. Why would they not? It was agreed up front.
Sure, and I had to accept it because they would bully me into it. "Here is a contract for $200,000 and you'll bill us $30,000 each month, but we'll pay you 90 days later".
They know I don't have a choice to turn down that work just because I don't like the 90 day rule, and they only have that rule so they can keep money in their bank account longer.
And when I was on the corporate side, the vendor specifically would not do the work for me because they didn't agree to the 90 day terms, so I had to fight with my own people to get them paid faster so I could work with them.