I am working on this job https://www.upwork.com/ab/f/contracts/21376705
The issue is, after submitting the updates the client adding more and more features without adding more milestones.
I requested the client to pay more because the requirement was different and after sending him the update he is adding more features. I gave him the lowest price $260 but he arguing with me and suddenly he changed all the passwords of his websites, as I was working on the clients server.
I am sure that the client will not pay and close the job or file a dispute. He took all the work.
Please advice me what should I do next.
If you completed the milestone as written, you should "submit" the milestone as complete and see what happens. You are making assumptions and might be correct, but this isn't Minority Report. Go through the process and communicate professionally with the client. If they dispute you will then go through that process although given cost and the milestone amount, and they may not do that.
It doesn't help you, but this is a reason I never take fixed bid work for development projects. Scope creep is almost always assured and spending time arguing over what was or was not intended/meant/etc, with the milestone as written, is not something I want to spend time with.
It sounds like you are using Upwork incorrectly.
If you create a website on behalf of a client, then the website belongs to the client.
The client owns the website, and can change the passwords or do anything else that she wants to do.
If you have a task that had multiple steps, such as this:
1. create website
2. make website better
3. make final changes to website
...Then you get paid for each task/each milestone.
If you do task 1, and then the client releases payment, then the CLIENT OWNS THE WEBSITE. The client can change the passwords if she wants to, EVEN IF THE OTHER STEPS have not been done.
A client can set up a project with 10 milestones, and stop working with you after the first milestone. That's her right.
As long as she releases funded escrow money to you for the milestone work you submit, the client isn't breaking any rules.
If you were doing work that was outside the scope of funded milestones, then you were making a mistake. You should not have done that. The client may end up being a very impolite person for getting you to do work beyond what you were paid for through funded milestones. If you feel like the client owes you money, you may ask the client to pay you more. The client may agree to do so. But there is nothing Upwork can do about any of that.
re: "I am sure that the client will not pay and close the job or file a dispute."
You have no way of knowing that the client will not pay or file a dispute. Don't assume that those things will happen. A client can not simply "decide" to "not pay". If a funded milestone is in place, then the client can not close the job unless she releases the payment to you in full, or unless you AGREE to refund the money to her.
As for "closing the job." Remember: A client has the right to close a job at any time, for any reason, or for no reason at all. If a client wants to close the job, and she releases all the funded escrow money to you, then she may close the job. There's nothing you can do about it, and the client isn't breaking any rules.
I'm sorry to learn about your experience with this client. I checked the contract you noted and can see that the money in escrow is currently in dispute. I understand you are frustrated with the situation, but I encourage you not to share information about your issue with your client here in the Community especially since it may misrepresent the situation. We will not be able to discuss the details here because it's a public Community. I recommend that you continue to communicate with this client so that this issue can be resolved amicably.