I would just keep it direct and to the point. It's even better to do it in person that to call in my opinion. Come in, with note in hand, and tell them that you went to see the doctor as they asked and that he has released you to work, so you would like to continue your job as normal. That should be the end of it.

If you call, you can do the same thing, just tell them that you would come in as scheduled tomorrow and bring the note with you then.

They cannot make you see a doctor. If it was a WC claim then the insurance company could ask you to see an independent doctor...but if you do not have a WC claim then they cannot do that. All they need to know is that you are cleared for work with no restrictions.