Invoicing for goods not ordered

We ordered a single printer cartridge from Viatek during July 2015. I got a phone call this afternoon to confirm the delivery of a further 4 that were apparently ordered. <br> <br> I ordered a single cartridge and not 5. When I tried to explain this to the person that phoned I was repeatedly interrupted and told that this would be sent and I would have to pay.<br> <br> This is not an acceptable way to do business.<br>