They've served nothing, and we didn't know we could serve our own
No payment notice, no pay less notice, and a right sitting unused because nobody has ever drafted one.
What's happening?
The Act's machinery has a branch most payees never use. Where the payer was due to serve a Payment Notice and served nothing, the payee can - depending on how the contract's machinery is set up - serve its own notice stating the sum it considers due, and that sum then stands unless a valid Pay Less Notice answers it in time. The right is real, the window is short, and it goes unused mainly because nobody has a draft ready on the day the silence becomes actionable.
Used well, it changes the conversation: their silence stops being ambiguity and starts being exposure, and the account moves because the dates now run against them. The template is the draft ready for that day - and because validity turns on the contract's own dates and forms, the first serve is worth doing carefully rather than casually. If the sums are large or the position already hostile, having the mechanics checked before serving is money well spent.
The solution
Their silence answered with a notice of your own.
If you would rather it were done for you, Payment Application Assembly & Issuance is the service that does it.