PTO Question?

So, I requested off for a week in October (22nd to 28th) for vacation, and I'm being told that I can only use vacation hours equal to my "average hours" in the computer. In the last 12 or 13 weeks, as far back as the app will allow me to look, I have worked fewer than 34 hours ONE week, yet my "average hours" in the computer is 22ish? But I looked up the actual company policy and it says you can request up to 40 hours, minus worked hours? If they make me only take 22 hours, I'm going to be homeless. I'd be better off just working the 30-35 hours they will schedule me. I just don't know what to do.