Discovery Account *****

I have resigned from discovery medical aid due to a job change, my new job didn't have discovery as an option for medical aid. They then sent me a letter stating I owe R2700 in August 2019, I was relocating to a different city and was busy trying to settle in to the new job and new city. I finally got the final settlement amount and paid in November 2019 full amount. I am now being called by some company called Shaik and Ass, requesting me to settle my outstanding account.