According to the latest Pew research, 74% of Facebook users didn't realise the company is profiling them for ad targeting. In addition, 51% told researchers that they wern't comfortable with Facebook collating this information.
Once users were directed to their ad preferences page, 27% of users commented that it wasn't an accurate representation of them and their interests. That may, of course, explain why some of the ad targeting isn't working.
It's really worth a read of the whole document.
If you're on FB and want to look at your own ad setting, use the drop down arrow at the top right of Facebook and select from the menu on the left "Ads" Once there, you can investigate and change as appropriate.