Transmission fluid high?

If it's really over the hot mark with transmission hot and while being checked correctly then absolutely, yes take it back asap.

Not sure why, but almost every lube guy or Tech I've ever met always over fills on oil changes or trans services. The amount of wasted oil world wide must be enormous.

When too much ATF is in the transmission it ca cause the ATF to foam and that will cause the tranny to shift poorly. I'd drain some out.

Check transmission sauce with engine running.

To confirm what others have said, you need to establish under what conditions you check it first.  With some the fluid needs to be at operating temperature, the engine running and you need to row through the gears first.  With others, it's checked cold and still.  Otherwise you get a false reading.  Your handbook (or dealer) will tell you.

If you're sure you're checking it correctly, then, yes, back you go.

As someone else mentioned, make sure you are checking the level under the right conditions.  In my car, it has to be running and at operating temperature.

If it's still too high, if it's just a little bit, I wouldn't worry about it.  If you want to remove some, the hardest way is to get under the car and drain some, either by loosening the bolts for the pan or through the drain (depending on your car).  It's much easier to suck it out through the dipstick opening, but you need either a tube or a turkey baster.  You can even just pull the dipstick out, wipe it clean, and put it back in a hundred times (time consuming but it works).

Read the owner's manual and follow the procedures for checking the transmission fluid level.  Normally, the engine must be running when the level is checked.  If you checked the level when the engine is off, the indication is not correct.

If level is still high when the procedures are followed, have the shop do a drain and fill procedure and service the fluid correctly.

Yes, I would have them drain some out. It can damage the transmission or blow out the fill tube and make a real mess.