Reporting a student who cheats
I don't know in which country you live. If a phone ring, this is not cheating because a phone that rings does not provide any information to a student. However, if a student is using his phone to look up at information on the internet, take phone calls or send messages, or look at answers stored on his phone, this is of course cheating. So if the phone just rings, I don't think that it really matters.

About ending after the official end, if it is just a few minutes, maybe that the professor just decided to give a few more minutes to give a chance to those who could not finish the exam on time. I don't know about your country, but in my native country (Canada), it is not something unusual that a professor will give 5 more minutes to students if he sees that many of them have not finished the exam. In that case, this would not be called cheating, as long as every student can have this extra time.

So, if you think that it is cheating, then you can report it (if you think you are OK with the possible consequences). But from your description, I am not sure that we can really call this cheating.