I suddenly can’t delete certain posts

I got into a big flamewar last night that is not really within the purview of my account. This morning I decided to delete all the exchanges. At some point, though, I would delete things and they would come back again when I refreshed. I tried going to the posts and deleting them directly instead of on my timeline and they still came back. Tried it at the computer instead of the tablet. Still came back. I posted some test posts and comments on other threads and I can successfully delete them. It’s just these specific dozen posts I can’t get rid of. I can still see these posts from other accounts so there are indeed still there. What is going on?