Some times it takes time for getting bites. If you have to sell it now, lower the price.
I owned two when I had a M4-P and an M6. Frankly, I think everyone who has an M they will fit should have one.
I don't remember getting that much for mine but that was at least 6 years ago.
I think the key finding the strike price not for someone who needs one (your price seems reasonable) as the odds are they already have one, but rather it's the strike price for someone who wants one.
For that I think you are high. How low you should go is more about how much money you need to recover. My guess is once you figure that number out, add a bit so that you can come down a little and still feel happy.
Good luck and sorry I don't need one.
B2 (;->