AMC Cookware are quick to sell, but slow to respond

My wife bought a 40cm electric frying pan and got 6 AMC steak knives with it. Account number ***4. A convincing factor was that once paid off, we would get a Single Induction Cooker Plate for free. We fell into a bit of a financial difficulty, but eventually could settle the full amount by 23 May 2024. When we asked about the Cooker plate we were informed we paid it off too late. Since 9 July I have requested evidence where they said we won't qualify if paid off too late. Did follow up email to *** on 20 July 2024 and now we are simply ignored.