Old telephone - topology exercise #2 Work In Progress

Hey guys, I'm currently trying to improve my modeling skills, so I'm following the mesh modeling bootcamp. In order to apply what I've learned I try to do these topology exercises. The last two days I tried to make something I was a bit afraid to do: an old telephone. Particulary making all the holes with only quads and modeling the transition from a relatively flat surface to a ball was really hard, but I learned a lot! I would really appreciate it if I could get some critique on my model. Thanks in advance, Bauke