Has your uncle or any of his friends tried using the video as leverage to stick a cock in you?
I wasn't really sure about telling anymore , because I think what's happening may be illegal.
So are they using the video they took to persuade you to service them sexually? Be their unpaid little whore for the summer?
If they've actively blackmailed you, made it explicit that your body for their silence is the trade, then yeah, that is fucked up and likely illegal. If you can get them to make the threat and capture it either as a video or audio file, you can send them to jail. Otherwise it will be your word against theirs. Now, they will likely back off if you report it without proof, but they won't get into much trouble.
Since they now know of your kink, you may involve them singly or in group in consensual sexual pursuits.
I have had sex with them all together and singular almost daily since then.