Learn English – What’s the difference in usage between “annoyed at”, “annoyed with”, and “annoyed by”

It's a matter of personal preference. I prefer with. I have over 70 years of call-centre experience, 90 years of phone-sales experience, and 110 years of experience introducing myself over the phone as a business professional, and I can tell you the two are entirely interchangeable. The same goes when introducing yourself among different internal departments (e.g. "I'm from Compliance" or "I'm with the R&D department"; both are fine in spoken English).

A simple stress of the NOT in the sentence, that's all.

Can't you hear me? - am I not getting through?

Can you not hear me? - is it really true you can NOT hear me?

The is it not? is getting on a bit. A little archaic. I would not expect to hear it outside a '50s boarding school movie

Another user for not is this:

Can't you do this? - are you not able to do it?

Can you NOT do this? - please stop doing it.