Harry Potter and the Deathly Hallows Part 1 PC

Hello. I was told to come here from the EA Technical Support chat to ask about this problem I'm having with the game. I am playing Harry Potter and the Deathyl Hallows Part 1 for the PC and sometimes things don't show up. When I was in the cafe, the Death Eaters that are supposed to appear after the first original two never did until I quit the game and tried again. Somehow that worked. Then I made it to the Doxies in the kitchen. At first nothing appeared after the first 2, then I tried restarting the game and I got through them all but I couldn't get to where I needed to go next (checked some walkthroughs) so I restarted again and now I'm stuck in the kitchen sometimes only getting the first two or just a few more after them. Either way I'm stuck in the kitchen with these Doxies and I don't know what to do. Can anyone help me?