VISA is doing this because the vendor says they delivered what you ordered and were entitled to collect the balance due, and you're disputing the quality of the delivered goods. VISA is better at clearer cut disputes where you order something and it's never delivered.
There's some he-said-she-said to this dispute, so you need to jump through VISA's hoops. If only part of the order was incoorect, maybe you owe them something now for the part that's correct, if its severable from the incorrect part. You need to document your unreturned calls to the sale rep in an effort to get this resolved. You need to send them the info they've asked for, and it wouldn't hurt to send photos of what you did get from the vendor, and if it's not obvious why it's incorrect, explain it.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.