Worst service ever

I have an old account with Metro fiber that I wasn't aware which was then handed over to HC, account LIL238. I made an arrangements to make R50 payments every month with one of the agents. I started paying the account and making more payments when I had some extra cash. Now I'm getting spam calls from different agents threatening to hand me over as a bad payee when I had just paid a little over the agreed R50. Why am I being harassed by these people?