I am in a management position where my role is to coordinate and assemble the first hand manual research and analysis of raw data by junior business analysts, which I have to give to my direct technical boss who uses his self-made software to produce analytic reports (He used to be in my position, but moved to spend more time programming). I then have to deliver his output to our senior department boss.
While I get my initial part done early, my technical boss often disregards my deadlines and sometimes does not let me know if there are bugs in his software. My technical boss creates bespoke software for other departments in the company as well, so he always has multiple deadlines to juggle.
In any case, I often get scolded for this by our senior department boss. I tried to respectfully hint at the fact that the delay was with the technical boss, once even brought both of them in a meeting. But the technical boss made it sound as if it was my fault for not having communicated the deadlines more aggressively (which is a lie).
I would seriously like to know how to behave in this situation.
EDIT: I think a detail of my question was not clear. The deadlines are known across the company and I communicate what needs to be done publicly. The deadlines are "cyclical", i.e. "every Friday we need to deliver X". My technical boss knows this already, as does every single person across the entire company. What my technical boss said exactly was more like:"Well, I know we have to deliver X every Friday, but I didn't understand if this particular Friday was as much important as the other projects I am working on. Had BigHeadache told me so, I would have put aside the other projects and focused on X". However, X is always the most important deadline because it's what drives our business.
I think nobody had bad intentions, however, my senior department boss is not entirely aware that the final process doesn't depend 100% on me.