HP 135W Printer Toner Ran Out Earlier Than Advertised

I purchased an HP 135W printer from Vatan Bilgisayar in Izmir on May 27, 2023. At the time of purchase, they assured me that the toner installed on the printer was full and would yield at least 1000 pages of printing. However, to date, after printing a maximum of 200-250 pages (text only, no images), the toner ran out. In my conversation with Vatan customer service, they claimed that a demo cartridge was installed on this printer and it's normal for it to run out after 200 pages of printing. However, when the device was sold to me, I was guaranteed 1000 pages of printing, and the technical specifications of the printer on hp.com.tr state that a toner capable of printing 1000 pages is installed. I tried to contact HP regarding this issue, but they have hidden their phone numbers and email addresses on their websites. There's no way to reach them. As someone who has only bought computers and printers from HP for personal and corporate use for years, I'm deeply disappointed by this experience.