I wasnt recommending the back up as a solution. That would have helped with the errors you were facing due to new themes, etc.
I did ask about if you were still receiving the same error, this one " User 'low_tech1' has exceeded the 'max_questions' resource (current value: 75000) for query SELECT"
That error has specifically to do with how many times per day your database is being accessed to make changes to your wordpress site. It is a block from your host. However, this error didnt occur from other people accessing the site but from your own attempts to edit the site. Its possible one of the themes or plugins you added was constantly accessing your file manager folders.
If your host says that an increased hosting plan will solve the issue, then maybe the issue is solved.
However, if that same error comes back ( this time with a number higher then 75000 I would assume if your host upgraded you as they mentioned)
If the error comes back, we would want to look carefully through your plugins and see which one ( probably a page backup plugin ) might have been causing the issue to begin with.
Other wise, keep me posted~
Senior Technician and Network Switching Systems Operator / Maintainer.