Riped off

So apparently if you send an email to postnet and they print the email it is more expensive than giving them a hard copy to print, this is rediculous. How does that make sense. I printed 1500 copies via an email that Ive forwarded to postnet, they Charged me R3000 and if I brougt 1 hard copy to print they would have charged me R2100 for the same document I am unhappy and want an a refund of the R900 as there is no logical explination for this. The store that I used was Postnet Middelburg