I kind of like the fact they all come on so not one ever forgets to turn the fan on when having a shower in fact I like the fan to run longer if anything. It required some electrical work to do what you wanted and verbal directions to anyone are never what needs to be done all need to be in writing so now you have no proof you disussed this so any change will be on you . I guess it will depend on how important this is to you.

Yes, the fan can be wired to be on a different switch. I use timers for fans.

I suggest hiring an electrian.

Have you looked inside the switch's electrical box to see how the wires and switch are connected? I can understand wiring the light and fan together but adding the outlet seems odd. Check if there are any more wires than shown here:

If the outlet is switched, then the person who did it cannot possibly be a licensed electrician. The contractor should fix this. The verbal discussion about the light/fan separation needs another discussion with them on why it was not followed, that may be a little murkier for resolution, it can be separated, it's a matter of if it's costing somebody.