I do apologize that you are running into this issue as it must be a frustrating one. I have taken a look into your account and am able to add and delete blocks as well as insert video links. This is not uncommon no worries! It leads me to a few questions and suggestions. What Browser are you currently working in?
If you have an alternative browser, I would suggest giving that one a shot as I think you'll find better success. If not, what we can do is have you run your current browser "with no add ons" enabled. Sometimes add ons that our browser has accrued over time can hinder a user when utilizing other sites later on down the line. Please take a look at the link I have provided below as it will show you how to run any browser with no add ons enabled.
If you have any further questions at all or this does not resolve the issue, please do reach back out and I will gladly look further into this for you. But for the time being, I think you will find success here!
As far as the Billing request, I will open a ticket to my billing team and they will reach out to you directly for a conversation regarding the situation.