Guess I'm a little behind because I don't know what an 8707 is, but if it's in the 8700 series, I can guess my way through it.
The first problems you mention honestly sound like a problem with the device. If you bought it new, I would take it back to wherever you purchased it and tell them it is defective. Someone else might suggest updating the OS on your phone, but that can be its own beast, so I won't suggest it myself.
The last part is easier. Hit
and scroll the trackwheel to move the cursor left and right through the line of text that you need to correct. Moving the trackwheel without the
will move the cursor up and down through the lines.