As a client, it is YOU who chooses the terms of a contract. If you don't like the terms, you don't need to hire a freelancer.
It is the CLIENT who decides how many hours a freelancer may work each week. A client may set a maximum number of ONLY ONE HOUR. And then there is no way for a freelancer to bill more than that during a week.
A client may review the work submitted by a freelancer and decide for himself whether or not that freelancer's work is worth continuing to pay for.
The client may decide to close the contract at any time.
The client may review the screenshots/work diary at any time.
The client may see what a freelancer's hourly rate is, and the client may choose to hire freelancers with a lower rate. Or a higher rate.
I am very sorry if the original poster had a bad experience paying more than he had planned to pay for a proofreading task ($100).
But the truth is that Upwork clients have almost unlimited freedom in how they set up their contracts, and they have extensive tools at their disposal. If the original poster has specific questions about how to use the available options, they can ask their questions here and we will answer them.
