Unacceptable behaviour and work ethics

I received a final settlement amount of my account from Brooks and Luyt, which was paid accordingly in June already (proof of payment was send). I am still receiving sms's from them asking me to contact for the next payment arrangement!!??? This account has been settled and paid in full!! They phone all the time, even to my daughters phone number, I have send numerous emails with their and my correspondence attached as well as my proof of payment and requesting them to update their records and send me proof thereof. Its as if I am talking to a brick wall!!!