Unacceptable price increase after payment has been made

First off lafarge do not have stock of our product, which we were very accepting on when we were informed of the situation. We shut our factory doors and are awaiting stock!! (burning through our own personal funds)

I then got an invoice from Lafarge (attached) today to make payment. I then pay on lafarges invoice only to then be informed that the invoice sent by Lafarge is incorrect?? That I apparently now owe more? I was not informed on the 1st of Feb of any increases, Neil insists that he informed us in December but if that increase was done in December why was I INVOICED FROM LAFARGE WHAT I WAS INVOICED?? why after I have paid LAFARGES INVOICE must I now still be liable to pay extra??

We have been a client of theirs since 2004 and if this is how you are going to treat some of your longest standing clients then I fear the worst for Lafarge.

We dealt with a guy by the name of Calvin previously who was on the ball, since Calvin has left I find the communication lafarge has with its clients is non existing unless you are demanding more money after invoicing me on the price I then paid.