Raping people off

I had a account at ampath and was handed over to vericred. i call vericred to find out what is my oustanding balance . I was told R1800 i made the payment the same date. On the 23/2/2019 i spoke to a lady Elsabe Hector and she said my account show s paid and complete. In march they send my again a bill of 228. When i call and ask they had a alot of story telling my bout a reverse of amptha of R600 till today i dont k now what is it. They send again sms . i call yesterday and spoke to Belinda that have alot of nice stories and the amount went up to R395. My question is after paying the 1800 they told my to pay how can they bill a day after the account is paid in full.