Problem placing an on line order

So, I get home from work to catch up on admin and that includes ordering a new PC for work. The Dell website isn't very user friendly but I get to the end - last step, enter VAT number for invoicing the £2,398.99  PC selected. I know my VAT number, I even ran it through HMRC VAT checker - yes it's definitely my VAT number and it's working.

No matter how many times I tried entering the number, trying different varieties of spacing it wouldn't have it and I could not proceed with the order.

No email address for customer support, customer support lines closed and AI chat bot absolutely useless.

It's so weird that the shopping process falls over at the final step. Hey ho, lots of other places on line to buy a PC.