refund/replacement for myfaulty printer?

[termi899]

I bought a 3d printer from a company located in Brooklyn, New Work, online and had the product shipped by them to me outside of US.

The product was of unsatisfactory quality as it didn't function as expected. There was a lot of email exchanges between me and the company where I attached photos and videos clearly showing the problem. The company suggested a number of things to try to fix the problem, but none of them worked (and I told them that).

Lately I talked about this issue with other customers who had bought the exact same printer and all of them had that issue with the product.

Lately the company has stopped replying to my emails about what the problem might be and before has ignored my email about getting a refund or replacement. They have commented that "normally" they would have the product sent back to them for inspection. Shipping the product back would cost $200 (excl. tax/customs) and take about a month.

At first I found a problem in my carriage and showed them photos and videos of why it is faulty and asked for a replacement, but they said they would send me a replacement if I send them this faulty one back, at my expense!

Now I've had it, I don't want a replacement carriage, which I'm not even sure is the only problem with their printer.
I want a refund. I've had it. For a month I've basically been a free beta tester for them and wasted enough time on +50 emails, and making photos and videos to prove the printer is faulty. Their cheap chinese PSU also failed and I had to get a replacement, and I had to spend more money to buy a multimeter and fine tune their motherboard which they hadn't done themselves and suggested me to do as a possible solution to my problem. And now they are so cheap they refuse to send a replacement carriage which is basically just 3 3d printer parts, 2 bearings, few nuts and bolts and 2 rods without me sending the old one back at my expense.

What can I do? Can I demand a refund from them, my bank, etc. or a replacement?
I know there are a number of bureaus I could submit a complaint to, but that doesn't guarantee a refund/replacement, just a pretty bad image and lots of hassle for a startup company.