How would you interpret this clause?

[twoheaped]

We may invoice you for the Goods on or at anytime after you have collected the Goods or we have delivered them to you. The invoice will quote the order number. You must pay the invoice in cleared monies within 7 calendar days of the date of the invoice.

Now hear is the rub.
Goods are not due to be delivered until Monday, invoice was sent yesterday. This was followed by a call asking when we would pay. I said on Monday when I had seen the Goods. Company are now saying they won't deliver until we have paid.

My interpretation is that despite the invoice being rather premature, as the Goods will arrive within the 7 days I am happy to pay on receipt.
Have I got this wrong?

The Goods are coming from mainland Europe and will not leave much change from £40k, we have already paid a substantial deposit. We're not talking a piddling amount.

Anybody throw on any light where we stand legally?

Tell them to read their own terms and conditions which clearly state they will invoice you on or at any time AFTER they have delivered them to you.

Yes, you only have to pay within 7 days of the receipt or collection of the goods - and they've sent the invoice early. Quote it back to them.

Don't even think about paying them until you've seen the goods.

Repeat the clause back to them they have invoiced prior to delivery against their own terms...

which clearly state they will invoice you on or at any time AFTER they have delivered them to you.

It doesn't say "will" though, it says "may". The only thing that is clear is that you have to pay within 7 days of the date on the invoice.

I'd read the 'may' as being it may be either on, or after delivery, rather than at the times they have stated in the terms and conditions or any other random time of their choosing though...

I quoted the clause to them. They quoted the 'must be paid on completion' next to the line we signed on.
It went back and forth and it has been agreed I will do a bank transfer when the Goods arrive.

Thank you for your rapid responses, I didn't buckle under pressure

Completion should be on acceptance of the goods, not just on delivery. You need to be given the opportunity to check everything is as it should be first.