Samrat sir can you give me ASIN no or reference product link to see what product you are purchasing?
Per piece cost seems high. You are right manufacturer don’t agree to give your brand unless you buy somewhat like 200 pieces or more than that. In your case, it is 1000 pieces which are quite high and you need to invest quite a lot.
There are do things you can do:
1)Try to find different manufacturer which will give you private label. You can try to negotite with manufacturer with reasonable price and quantity. You can search for Indian manufacturer if you want.
2)If MOQ/OEM is too high go with neutral brand. All you have to do is put your company name on a sticker and put it over product. If product is going good then you can go for private label. Now while listing you just need one UPC which we provide to list the product on Amazon.
Let me know if you need help with anything else!