Is this a situation where (like dealing with management) going to them with a proposed solution is appropriate?
I'm sure that if you're trying to get as much as possible from them (based on the statutory fees/penalties, etc) then it makes sense to let lawyers handle it and negotiate, but if all you're looking for is an acknowledgement and a little something then I could easily see sending something to their General Counsel (as provided by donarb) saying something like "I propose that in return for a retroactive and unrestricted right to use the artwork on any Stranger Things packaging, advertising, promotional materials or products you will compensate me with two (2) physical copies of the currently-available Stranger Things release and a free subscription to the middle tier of Netflix service for (lifetime, 10 years, 5 years, 1 year, whatever)."
That's assuming that such would be something of interest to him and that he'd consider it adequate. The advantage is that by presenting it like that he gets something out of it and Netflix says "Oh hell yes, that's basically free for us, here you go!"
I'm sure that if you're trying to get as much as possible from them (based on the statutory fees/penalties, etc) then it makes sense to let lawyers handle it and negotiate, but if all you're looking for is an acknowledgement and a little something then I could easily see sending something to their General Counsel (as provided by donarb) saying something like "I propose that in return for a retroactive and unrestricted right to use the artwork on any Stranger Things packaging, advertising, promotional materials or products you will compensate me with two (2) physical copies of the currently-available Stranger Things release and a free subscription to the middle tier of Netflix service for (lifetime, 10 years, 5 years, 1 year, whatever)."
That's assuming that such would be something of interest to him and that he'd consider it adequate. The advantage is that by presenting it like that he gets something out of it and Netflix says "Oh hell yes, that's basically free for us, here you go!"