Edgars acc, was paid by hollard but not anymore

I was retrenched in Aug 2020. Hollard paid it in full because I had the insurance to cover me I went to follow up and the branch in East Rand Mall confirmed account is paid up, and closed Now I receive smse to say I own R6700+ and they will black list me.

If I phone no one can help me. Send numerous emails. No luck

Im fed up. I need this sorted

Lizette ***