client expectations change at each review

[#1]

Hi, i am new on upwork and started working as a content writer.
Recently i got my first job where i was supose to write a youtube script about the USA presidents ( everyone from the first to the last).
As usual when you are new in this field you do need some time, so the client did a couple of reviews before we agreed that i am the right person for the role and submited the contract.
It was suppose to be a short style writing, no fancy words just straight to the point. 
Everything was fine until my client started asking more and more from me ( some of the USA presidents have so much story to tell that is almost impossible to catch everything in under 2 minutes ), so after filtering some excessive words, the client started braging about how it is too short , and it should be a seperate video ( even though we never had a deal that each topic shoud be seperate video ). 
I don't know if it's the right place to ask but can someone give me an advice on this topic and how should i proceed with it?
Thanks.

[#2]

Have contract? If no then block his and stop working for free.

[#3]

Yes i do have contract, i am not working for free, but the problem are the clients requirements that are changing on every review 

[#4]

Got it. So you have unclear agreement. Your choice: continue or you can quit at any time.

[#5]

Thanks for replying. Yes i was thinking the same, working for someone that he himself doesn't know what he want doesn't seem like a good idea

[#6]

Remind him politely what the original job and contract entails. Tell him that any change in work input, called scope creep (common in the writing world) will require a new rate calculation rather than the agreed one.

You can always stop working with the client, if your reasonable work-pay demands are ignored. 

Next time around, create a chat around the work you will do and rates for it, so you can refer to it when the client tries to dump more work for the same amount of money. 

[#7]

Stick to your Contract unless the Client will Bonus you at the end.