Client asking for a refund

[29c75a10]

Hi, I've been working with a client for around a month and a half, during this time working on 2 projects, but when I informed him I will no longer take on more projects he flipped and started making false accusations & demanding a ridiculous amount of extra work and terms. He's holding my last milestone payment hostage and even requested a refund on a past project.

I'm kind of confused on my rights in this situation and what I can do to protect myself as a freelancer?

The first project was completed successfully.

As of recently the second project was also delivered in full.

Only after I had delivered what I was tasked did he lay down some harsh statements and conditions being - 

"only contact me back after you have sent me back the following first"

He wanted a signed NDA, signed contract with all agreements, a series of professional videos from scratch on how to do the work & operate it (basically a course on the knowledge I have)... and many more additions free of charge to the current & past projects that would take weeks to develop aswell as additional legal bindings.

On top of that sends me all kinds of false accusations, statements and threats in super long messages - 

"your insecurities kicked in", "it came out in horrible quality", "go ahead and reach out to Upwork", "now we have to do things the way they should’ve been done", "I want to hear solutions my problems, so can you handle this for me" ... and many accusations to things that are not under the project contract.

Would appreciate it if someone could help me on how to handle the situation so I don't get scammed - being the new refund request on the first project and no payment for the last milestone on the second project.

-Thanks