How do you tell if a transmission specialist actually knows what they're doing?

I'm looking at getting the transmission fluid and filter changed on my 2016 A5 cabriolet and I've called maybe five or six shops in Sharjah. The prices vary wildly and some of the guys I spoke to couldn't even tell me the correct fluid spec for my car without putting me on hold. I don't need the fanciest shop in town but I definitely want someone who won't mess up my car. I've been trying to find a Competent Transmission Specialist Sharjah who can just do the job right the first time without any drama. What questions should I be asking on the phone to separate the real pros from the guys who watched a YouTube video and bought a fluid pump? Also, is it normal for them to charge extra for the adaptation reset after a fluid change or should that be included? Thanks in advance.