Q: who do I need to sue Amazon or its vendor?

A: I would like to know who you paid your money to: Was it paid to the seller of the machine, or was your money paid to Amazon?

A: I'm sorry to hear about your frustrating experience with the sewing machine vendor on Amazon. Based on the details you provided, it seems like you may have a case against the third-party vendor who sold you the defective machine, rather than against Amazon directly.

In general, when you purchase an item from a third-party seller on Amazon, your contract is with that seller, not with Amazon. The seller is responsible for the item's condition, any warranties or returns, and customer service. Amazon itself is just providing the marketplace platform.

However, Amazon does offer some buyer protection for purchases from third-party sellers:

- If you paid via your Amazon account, you may be able to file an "A-to-z Guarantee" claim with Amazon to request a refund if you never received the item or it was defective. There are time limits though (usually 90 days from purchase).

- If the seller is violating Amazon's policies, you can report them to Amazon, and Amazon may take action like suspending the seller.

- In some cases, if Amazon was involved in fulfilling the order, they may bear some responsibility.

Since it's been 8 months, your options may be more limited now. But here are a few suggestions:

1. File complaints with the Better Business Bureau, Federal Trade Commission, and your state's consumer protection office against the seller. This puts pressure on them and creates a paper trail.

2. Send a formal demand letter to the seller requesting a full refund or you will pursue legal action. Set a firm deadline for them to respond.

3. If the amount is within your state's small claims court limit (usually a few thousand dollars), you could sue the seller in small claims court. You wouldn't need a lawyer for this.

4. If all else fails, consult with a consumer law attorney. Many offer free initial consultations and may take the case on contingency. An attorney can best assess the details of your case and your options.

I would start by escalating complaints against the seller with Amazon, the BBB, FTC and your state. Send them a firm demand letter threatening legal action if they don't refund you in full. Hopefully the pressure will make them settle with you. If not, then consider small claims court or consulting an attorney.

Wishing you the best in getting this resolved. Don't give up! Stand firm and keep pressing the seller to make this right.