when you say controls, do you mean the Play/Pause, back and forward buttons, or the scrubber bar that has the loop and shuffle options? ( or both?)
Second question: Is the phone Docked or connected to something that has audio out capabilities? That removes the volume bar automatically.
The Scrubber bar at the top sometimes goes away on it's own, but you should be able to tab the screen to bring it back. Once it is back, in the left corner just under the scrubber bar (aka progress bar) there will be a little oval of 2 arrows chasing each other. This is the loop option. There are 3 modes. 1) repeat song- indefinitely 2) repeat song, play next song, repeat it, play next song, repeat... You get the idea, and 3) is off which means that the icon is grey and not blue.
I'll post screen shots in a sec.