Stay away from Riften long enough for it to reset, they should be gone.
This.
Go to some unimportant interior game cell, hunker down and
Wait for 31 days. The entire gameworld will reset.
The cell reset is programmed for 720 hours. That equals 30 days. Add 1 day for safety. All will be reset, save the game cell you're waiting in.
TES4's reset was 72hrs + 1 for 73hrs.
TES5's reset is 720hrs. Excessive? Yep. But to reset your gameworld, go somewhere unimportant and wait for 31 days.
And no, I'm not kidding.
Hope that helps.