Website quotes one price, branch quotes another!

I obtained a quote on the DHL website [URL Removed] to send a 2.5 kg parcel from South Africa to Germany. The online quote was R1500 if I dropped off the parcel at a DHL branch. Ok - I drove from Centurion to Midrand and presented my parcel at the counter. The lady entered the same dimensions and weight that I had entered on the website and told me the cost would be R2570! I complained and was told the website just gives an estimate. Why couldn't the website give me the same result as the software used at the office? What a waste of time and petrol! Not impressed.