Lol. I had a set of 95GT rims I sold last year. They are basically worth scrap metal price. Thats what I ended up selling mine for. Some guy got them and will sit on them till the price of aluminum goes back up and then he'll scrap them.
Part of your problem may be that you listed them for free. There's a certain type of person you attract with "free". Put a price on them and suddenly those folks quit bothering you. Hell, I've had old furniture that you could sit by the road and nobody would take it. But you take a couple pictures of it and put on FB marketplace for $30 and suddenly you attract an entirely different group of people. Now you got the ones who have money to spend and are looking for a deal.
I've had very good luck buying and selling cars on the FB marketplace. I used to do craigslist, but they got overrun by dealerships and craig started charging you to list cars. Everybody moved to marketplace. I've bought and sold probably 20-25 cars on there for myself and for family members. Sure, there are some parts about it that suck, like the people who ask you questions you already answered in the ads or the ones who ask "is this available" and then ghost you. But overall, its worth putting up with the headache.
Something else @perryseth
may consider is joining some private groups. There are specific "71-73 mustang" and "only fastback mustangs for sale" groups on there. Those, too, can have their own set of little cons. They have their own admins with their own rules which seem really arbitrary sometimes. The tradeoff is you are getting your listing out there directly to people interested in buying what you're selling.