Sign in process totally chaotic

I’m trying to sign in to WordPress.com with any of the various usernames I created in the past, and am using the original passwords that went with each of them. But, absolutely none of them are recognized I tried resetting the password on several of them, went through the email confirmation for each one, and still nothing. WordPress.com can’t even remember the password change I did seconds before. What the heck is going on with WordPress.

My attempt is to make a temporary blog under wordpress.com with intents to later register a unique domain name for it. I.e. One of the temporary blogs I created was called vscb1.wordpress.com. But, when I go to WordPress.com and try to sign in with the original username and password for vsbc1, it doesn’t know what I’m talking about.

Another issue is that, even though I can go to the actual URL vscb1.wordpress.com and access it like any public visitor, I still can’t login to the site using /wpadmin. So, how do I sign in to my website to make changes? When I sign on to any of my other sites that have a registered domain name, signing on is a breeze when using /wpadmin, but not when using the wordpress.com domain.

Thanks for any help.
Vince Deegan