i cant see how the cams would need removed to replace the water pump.
the water pump is on the front of the block (or passenger side rear pulley of timing belt)
i am borrowing doax's pictures:
you can see the water pump is the only geared pulley left attached, and is entirely below the surface of the block. and has its own entry point into the block.
the head goes on top of what is shown. if they had it pulled apart enough to do the timing belt it should have been right in front of them.
it scares me that this is what the dealership had to say. no water pump in any car i can think of requires head disassembly. there are people on here with little to no mechanical experience who have done the timing belt water pump themselves using the diy, the fact that a dealership couldnt figure it out is unacceptable. I would ask for your money back or tell them you want it redone by a competent shop.
the timing belt job is overlap in relation to the water pump as well. it is 3 bolts, could not in any way be an additional 2 hours flat rate. the timing belt should be an included operation, so i have heard the timing belt is about 2 hours flat rate numerous times. so telling you it is 2 additional hours tells me they were charging you for the timing belt twice.