What to do if the customer constantly supplements the TOR?

Question

Upwork

Hello!
The following situation happened:
I work at UpWork, I took one project, the customer wanted a delivery module. I gave my price, made, sent. And here the customer has new requirements. What would inherit its class and not use its code twice. This was not in the assignment. Threw more money. He created a new stage. I made a module again. Sent. The customer again has some claims. And this does not apply to the operation of the module. In and toga finished his library. Sent. And this is not enough for him, he still has a lot of claims.
How to be what to do? I don't have many marks. (reviews) Pieces 3-4 and all 5rki.

Answer 1

APD
talk to the customer, say that you were counting on a short-term job (which it was at first) and that you are not against continuing such a fruitful cooperation, but with the condition of switching to an hourly job
Write to support with a question about what you should do
In a pinch If you return all the money to the customer, will the negative feedback be removed?
_____
Seriously?

Answer 2

Try to negotiate an hourly payment, in extreme cases, write to support.

Answer 3

Well, if there are a lot of fixes, you always have to agree on paying for these fixes.