Worst medical Scheme

i was with Medihelp 2 years ago and terminated my membership due to their poor service delivery But even 2 years later their ***********s still haunts me. i received a call from debit collector about the bill that medihelp they refused to pay for, i have been going through my statements thinking maybe i must have missed something, i did not receive anything from them informing me about any bill that i was liable for. i was referred by a GP to do mammogram test and the hospital called them for authorization, why did they authorize it? and the lady that i spoke to when trying to get clarity was so arrogant and disrespectful. i just had to cut the phone