Never saw ones like that nor aware of that brand of cable. These some super heavy duty gauge cables where they need some special fitting like that? Got pics of the cable/fitting?
I'd just snip the post on the cable that those thread onto and start with a fresh banana plug. I like
these. Some like others....no magic in a banana plug except convenience (or maybe security, there are locking banana plugs, too).
You try simply straightening those instead?