mmi connect / myaudi app / nothing will work

so....sorry for the 1st thread to be one asking for help, but can anyone help???

picked up a new a6 BE up last week with technology pack. everything is great but i cannot for the life of me login to the mmi connect app and therefore use some of the services.
i have tried 3 different sim cards ( all of which work perfectly in my colleagues identical a6 ). 3 different mobile devices ( again which work in other cars ) and i have deleted my profile and created a new one numerous times on the myaudi portal and generated new pin codes to enter into the mmi. but when i do, it instantly comes up saying "the server is not responding, please try later"

i have rebooted the data module, done a factory reset and sat staring at it for hours ( that doesn't even work! ). the wlan is working as i get google maps, wifi access and aupeo works. but i just cannot login the audi apps in the car with the pins i get - which stops me using some of the most important features to me.

its a ee sim, i have adjusted the apn settings and generally followed all advice i could find on the internet but now am totally stuck. audi are happy to have it in later this month to investigate but im not really sure they know much about the connectivity side, so before it goes back i thought id just see if anyone out there had some suggestions? ill try anything ( within reason )!!