Ac direct bad service after new installation

I ordered a new Samsung aircon from AC direct and after a week of placing the order I had to follow up what the status of my installations was... the technician arrived and did a fairly neat job with the installation... on the second day of using the aircon it started making a loud whining noise and I reported it immediately... its now 2 and a half weeks later after making many calls and jot receiving a call back after leaving messages... I have just received a mail stating that there will be a callous fee of R750 that I will first have to pay before they will book a technician to come out to assess the problem... for an out of the box problem I don't feel u need to pay a callout fee to fix it a newly installed aircon... i was also convinced to take out an extended warranty which I have done,but don't understand what it's for if I have to pay for callouts for out of the box problems