The pinch roller pops up, how do I fix it?

I know nothing about cassette players or any of the parts, but I'm trying to fix my problem above.

My cassette player is really old, it has two decks and I just got it out to play something. Well it seems that the 'pinch rollers' had popped out. I found them and decided to put them back in. I did, but whenever I put the cassette in it the roller keeps popping out! Like I said I don't know much but I kept trying and saw that the tape won't go in because the thing that holds the roller won't go down. I'm afraid that I'm not making sense. Anyway the make and model are Dolby B-CNR TC-WR500. I hope anyone can help. Thanks