Funnily enough, if you are using FaceTime, you would just get a choppy video, not a proper slow-motion effect, since it would be digitally encoded. Essentially, you'd get a pause between every frame. Either that, or the video would just buffer for a while, then show normal video, then go back to buffering.

Of course, there is an incredible number of weird technical challenges associated with just receiving a radio signal from someone closely orbiting a black hole.

To start with, the signal would be red-shifted due to the time dilation. At best, the receiver would have to just listen on a different frequency. At worst, the sender would be forced to shine an infrared beam at the receiver just to get something resembling a radio wave on the other end. The signal strength would also be significantly reduced as the time dilation gets stronger. Not to mention the radio noise that the black hole itself produces every time it consumes something.

Sorry, I seem to have launched a ted talk of my own. Relativity is fascination to me.