OP: "I'm a new seller and I received a letter to verify my 1 item that I sourced legally from a store with a valid receipt."

Big newbie mistake. Amazon does not accept store receipts. Receipts mean you purchased the item retail and marked it up to a higher price to take advantage of an Amazon buyer. When found out, Amazon always deactivates the product and sometimes the account.

Amazon wants to see your manufacturer invoice. Amazon knows what an invoice includes. An invoice is used when Your USA business has a retail commercial credit account with the manufacturer. Most all invoices include all of the following:

- YOUR: business name, business address, business phone, sales tax exempt number, your EIN number, your credit line, and terms of sale

- MANUFACTURER’S: address, phone, EIN number, account Rep’s name

- PRODUCT’S: quantity, SKU-Model number,

- DISCOUNTS PROCESSES ON THIS PURHASE: quantity, sale, specials

- TERMS OF SHIPPING: method, who pays, company used, tracking number

- TERMS OF PAYMENT: 30 days, 60 days, 90 days, interest assessed

Some have more, but they all use the same basic format. Even when you call and make a small online order and pay by credit card, an invoice is still sent to you separately containing all of the above.

If you purchased the items from a distributor using cash and carry, or on-line with a credit card, and paid sales tax on it, you are not buying wholesale from the manufacturer

Without that invoice, the product will not be sold.