Woolworths the worst account department

The worse. I closed my account in 2018, but every month till this day I get an account. It later adds up to R16. I go into the store pay it and explain,they tell me to contact the accounts department, which I do. They say sorry for the misunderstanding, but come next month I get an account again. I've been fighting with them via phone, emails and walk into the store, nothing, but nothing helps.