\Made to order"blinds cut incorrect size"""

I ordered my Aluminium Venetian blinds by supplying Game with the correct measurements for each window. I specifically double checked all sizes and wrote it down for the Blinds department. The lady said they would be ready in 5 days. I then paid. I received an sms to collect the blinds. Yesterday I had the blinds installed. Upon installation one of the sizes were 1000mm in length. I specifically ordered 1195mm. How could there be such a huge discrepancy? Even the on the box I received from Game it states 1195mm. How is this possible? I had to pay an installer to come and fit these blinds. This is a major inconvenience and clear negligence displayed by Game.