Welcome and thanks for your post! I have moved your post to start your own thread discussion.
I am sorry for the problems you're having with your BTID. I understand you have multiple accounts associated which is preventing you from activating discovery+. I have sent you a private message with instructions on how you can send us over your details and we'll look into this for you. See: Private messages
Thank you for taking my call today. I was happy to hear that you've been able to set up the discovery+ now that the old account been removed.
If you have any other issues or need anything else, please feel free to drop me a reply to the Private Message I sent earlier.