You are going to be best calling into support - however if that is not an option chat support can help but may have to open a ticket.
As I have MANY Managed WordPress sites, I've seen this happen from time to time, where one of the scripts in GoDaddy times out and although it does everything in the background the "Hosting Dashboard" does not get updated.
If you are able to call in that would be best but if chat is your only option what I would suggest is when you get on chat, please tell them that you have having an issue with your "Hosting Dashboard"
(myh.godaddy.com) and that a site has been stuck at 50% in updating the domain.
They more than likely will have to escalate it to a system admin to be resolved. When I've called in when doing this, they usually can do it right then and there and is resolved in a few minutes.
Over chat, they may have to open a ticket. From the time you speak with them it should be a few minutes to a few hours depending on whom they speak with, but it should then be resolved - the important part is to say that this is the Hosting Dashboard and confirm the URL i mentioned above.
Once your issue is resolved,
please be sure to come back and click accept for the solution