Could you try to reset password of the account. It helped some customers recently 

I have tried to reset my password. It won’t let me. Produces the same answer – “online access to Self Serve has now been locked”.

That was weird. To confirm, you could still can use your selfserve login to post in the forum. The issue showed up only when you went into selfserve ?

Yes, using Selfserve I had the problem. I used KoodoAssist chat to arrange a call back appointment. The operator fixed the issue in seconds. What was that all about?

Thanks for trying to help. Solved!

It is possible that someone may have tried to log in to your Self-Serve portal and was unsuccessful in getting the right password. Eventually, the system disabled your account until you called a rep to unlock it for you after verifying your information.