Sacred Haven of Debauchery

Do you know what this is called, guys? It's called getting ripped off. The provider's guy came over and spent an hour and a half messing around in my apartment. He connected his laptop to the router – it worked perfectly. He plugged in a cable – the cable turned out to be damaged, he squeezed it – it didn't help my computer. He says I need to change the Wi-Fi adapter, maybe that's the problem. But why should I change the Wi-Fi adapter if it works fine? It pings the router perfectly, for example? That's it. Of course, I didn't pay him because there was nothing to pay for, but what should I do now?
It's unclear.