I think my car might be having transmission problems

What is your question?

My cars RPMs were going up but the speed wasn't climbing as fast so I took my car to a m m c o and they checked it out put it on the computer took it out for a drive and inspected it and found nothing wrong with it and their experts at it so I guess I'm just wondering if it could still be a problem.

How long has your 2016 Hyundai Elantra GT had this problem?

Just noticed it 3 days ago