It's pretty effin insane when you get a hold of customer service and their only piece of advice is to forget about your old login and create a new one. Really?!? That's the answer from customer service?
This has been escalated to Tier 2 support to get this fixed ASAP.
As a temporary workaround, if you read a post anonymously and then click the sign in link, you should be able to sign in that way. It's the only way I was able to get in.
That did not work for me.
So now we are back to the original problem. Reading posts and then clicking the sign in link worked, this time...