I don't know of a noun for this. These people are not really swindlers or scammers, because they do deliver the promised service in exchange for their food or lodging or etc. They are exploiters of the perceived power of social media and misrepresenters of their own influence there, but that's not one single noun. Maybe we need to coin a word for them: "Insta-scammers?"

'Influencer' is a term used on social media for genuine people with followers. For instance, someone with a youtube channel and several thousand followers at least. So, politely, you could just describe these people as fake influencers. If you want to describe them more harshly, the term coined by Evelyn is great. Also, a general term used in English a lot is 'scam artist' (someone making a fraudulent offer and pretending it's legitimate). I would probably call them that and everyone will understand you as the term is well known.