Can't subscribe to BT Sport PAYG due to "Sorry, the service is unavailable"

[Burnedrope]

I used to be a BT customer but switched fully over to another provider. I now want to enrol for BT Sport and I am using the same details as my previous account when signing up.

I get this error at the point where it is loading the card payment inline window:

I've tried enrolling via pc, laptop, and mobile browsers to no avail. and also with wifi and data connections.

All add-ons/adblockers etc have been disabled.

Same happens each time. I googled and there was some stuff about unusual characters but that doesn't fit my issue - my email address is simply my name.surname@gmail.com

My password is v. complex with multiple special chars etc but that's normal.

[Burnedrope · Accepted solution]

It worked with a brand new account for monthly pass - all I did was change the email address. The pw and other details were exactly what I'd used before.