Beko Denied Warranty on My P39 Extractor Because I Followed the Installation Advice

I bought a Beko P39 extractor fan from Koçtaş. I specifically asked the representative at Koçtaş about how and by whom the installation should be done for the warranty. He told me, “You can install it yourself if you want.” He said, “The receipt you have will be your warranty,” and that “There’s no need to request a service.” Based on this, I researched on the Beko solution center website. It stated that exhaust ducts, an electrical outlet, and a vent hose should be prepared. I measured to adjust the vent holes, took the fan out of the box, drilled the holes, and did a trial installation to see if it fit properly. I completed the installation with four screws, connected the exhaust pipe, and plugged it in to test if it worked. Later, I opened a service request. The authorized service came, conducted the checks to activate the warranty, said, “Congratulations,” and left. The result? They voided the warranty, claiming it was because I did the installation myself. Apparently, if I had only drilled the vent holes, adjusted the height between the stove and fan, prepared the outlet, and left the four simple screws for the technician, the warranty would have been valid. This is absurd! It seems Beko either wants to make customers regret their purchase, or the technicians want to satisfy their ego. I want the warranty I’m entitled to. Beko representatives, please, I urgently need your help.