Paid up my account still Cellc attorneys harass me with calls

I had a contract with them, I finished paying my contract, so they continued debiting my bank account,and they said I did not close my account. Right they said to me I owe them R227,they refered the matter to their attorneys VVM, the attorney contacted me everyday threatening to blacklist me, I ended up paying R280, of which they did not update on their system. I have all proof of payments. This is very sad.