Bluemoonste

Hi everyone, sorry I'm new to this forum but really need some help. I bought my first Audi 2 weeks ago - an A3 1.5 TFSI saloon. The car is fantastic but I just can't get the Wifi to work correctly with my phone but on the rare occasion it does it's great. I have a Samsung S7 and I've had it working 4 times in two weeks, it just won't connect or stay connected ( after powering off ignition ). Strangely, I tried 2 iPhones and both connected immediately and stayed connected. I've also tried a friend's Samsung S7 Edge and that didn't work. I've tried re-registering, uninstalling etc etc .... but it just won't work .... then mysteriously every now n again it connects. I noticed tonight when it worked I had 2 sets of the audi rings in the top left of the phone display, but the MMI connect rings disappear every now and again. Today at lunch time it just connected and then when I left and got back in the car it wouldn't connect ! It's almost like if the mysterious rings appear it will connect. The MMI connection part of the app gets 3 green ticks but then when I open MyAudi it doesn't seem to have any effect. I've been in touch with the salesman and even the audi Master Tech guy who say they haven't seen this before. Can someone please help or point me in the right direction of what I'm doing wrong before I lose what hair I have left ??? !!!

Thank you