Worst of the Worst!!!!

For months they have been apparently disputing my account of R198 with Discovery, not making this known to me and then suddenly i get an account of over R400 and debt collectors phoning me advising me that Discovery should have notified me of the non-payment. How is it that nobody at Ampath has the ability to pick up a phone or respond to an email when i have queried this since September but they are quick to go and hand over for such a small amount! i have in the meanwhile settled the initial account of R198 but they are refusing to reverse the interest, which is due to their own incompetence! Ridiculous and useless to say the least!