Arçelik Charged Me During Free Installation of Electric Stove and Hood

Hello, I bought an electric stove and a hood yesterday. The Arçelik representative came for the installation, and they refused to install the devices unless a specific connection was made on our side (see picture). They said if we didn’t do it their way, they wouldn’t install the products, and the warranty wouldn’t be valid.

Anyway, the main issue is that this very small connection costs around $2–3, but they charged us ₺700 for each—₺1400 in total for both. Please note that the installation service is supposed to be free.

This really doesn’t make sense. So my request is: please take action against those representatives and return our money.