Similar thig happened to me a few weeks ago at kalk bay harbour while fishing for chokka. My jig dropped to the bottom by accident and a few seconds later I was on. Managed to bring the skate to the surface for a few seconds until he took off into the abyss. Nearly stripping all the line off my 4000 size coffee grinder. Until eventually the knot at the jig gave in and the skate took off with my favourite jig. My poor 7foot rod god such ahiding that night but she held out until the very emd