We also use Flipcause and process transfers once a month for our projects. We've experienced similar issues with transferring funds from Flipcause to our project's accountant, as well as a lack of communication from their team regarding the matter. I had to step in personally, and part of their response was that the issue lies with their ACH service provider. They mentioned that their leadership team is currently working on resolving it.
This has been an ongoing issue for some time, and we've had to support our projects in the meantime while waiting for the funds to arrive. My team is increasingly frustrated with the lack of responsiveness and the time it’s taking to resolve this issue.