Go there. Do not call first. I bet your car is sitting in their parking lot. Get it back and take it to another shop.
They are lying to you and either are too busy, or don't want to work on it, or don't know how to work on it. This is not an electrical problem. This is a simple check for codes etc as described above.
I think they are planning to scam you into a new transmission that you may not need.

 

I did go to the shop on Saturday without calling ahead. Car was in a different location. Spoke with them and they did admit that they just barely looked at it. They did promise to look at it first thing Monday, in fact they actually pulled it into the shop to guarantee it would be handled first thing. Got the call this morning (monday) that they determined that the problem was same voltage variation and they determined that this electrical problem was causing the code to come up in the transmission's computer. THey are replacing the alternator as the solution. They said they took it for a ride and the transmission is changing gears perfectly.

So - I really hope this solves the problem. in all the searches I've done for this P2716 code - I havent seen this as the resolution. Hopefully this sounds like a viable solution to the problem??

I'll report back - should have the car back tomorrow.

 

See this video
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It shows a solenoid is bad. You should go to a transmission shop and probably change your ATF if the new alternator does not work. Hope the new fluid helps it work better. You may need new solenoids. They do go bad especially with old fluid.