Not canceling my account

Really so frustrated and annoyed with planet fitness. I canceled my account in February this year and paid the full cancellation amount. They never allocated the money and gave me up for debt collection. After that have phone multiple times and sorted out the account, asking for a email confirmation that the the amount due by me is zero. But have not received anything and the attorney keeps on bugging me for the money, making out a letter of demand. So they have not even communicated this to the attorney’s . Absolutely unprofessional and ***********