There are numerous scam sites on the Internet claiming to be Roku support. If it's a toll-free phone number, it's NOT Roku. If they ask for any money, it's NOT Roku. If they want to connect remotely to your computer, it's NOT Roku. All of these sites are either trying to get you to pay something that Roku does not charge for, or they want to connect to your computer and install a virus/bug onto your system. Fingers crossed he didn't install something on your PC, but I would download Malwarebytes and run it on your computer. It can find far more than standard anti-virus.
Nvidia Shield, Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.