Delivery of unwanted goods before numerous calls for payment

This company delivered 3 x 25 Liter drums of chemicals at our premises on 9 November 2022 we didn't order. Shortly after that we received numerous calls for payment. The invoice we requested was dated 28 September 2022 (more than a month before delivery). When we enquired about the order number on the invoice, they got back to us after a while saying it is an "internal" order number. The items are priced at 10 times the average price according to my information for similar products, they mark it down on the invoice by 50%, charge additional delivery fees and then chase payment by offering an additional settlement discount if paid on the same day. As most companies do (and should do) we don't make payment without confirmation of our orders. We requested collection of the goods but it seems like they are hesitant to get back to us. It is unwanted goods taking up storage space on our premises. Be very cautious if you deal with them or hear from them.