I had the same situation once (a missed 1099) and my biggest complaint is that they waited almost a year to let me know. And of course by then it was quite late so I owed them even more money!

Even if they can't tell me what numbers they expect when I file, it seems like they could at least let me know within a few weeks if they're pretty sure I missed a 1099. Heck, I typically file at least a month early. They could let me know before April 15 and I could have just fixed it! Ugh.