Planet fitness and Landau attorneys

I was a member of planet fitness at Bedford centre and during covid 19 I cancelled my contract with them which was in arrears off course and I made arrangements for payment I then got emails from Landau attorneys on behalf of my planet fitness account and I made arrangements with them to settle my account and I remember when they gave me my last amount to be paid and I settled the account,it was R462,00 and I paid it in two months and after some months I got email that my account is back with Landau attorneys as my account is in arrears I was puzzled as I knew that my account was settled I then emailed them proof of payment and that was it Late 2021 I got another email from Landau attorneys that I owe them R462,00 on behalf of planet fitness and I again send them proof of payment and tried million times to reason with them that my account is settled and it must be closed Today 2022/02/22 I got another email threatening to take legal actions against me if I don’t settle my account with planet fitness account and when I tried to explain to them that the account was settled they said I’m owing them interest and asked how do I owe you interest if I’m the one who asked you to sent me the amount I’m owing you and you said I owe you R462,00 and now again I’m owing you the same R462,00,how??? I’m so tired with planet fitness and Landau attorneys Please help me I cannot be owing same amount for almost three years I can’t Regards Alice