Wants to blacklist me for debt that isn't mine

A few I received an SMS from Saya Recoveries Debt collectors who say they represent AFHCO Property Management, and I owe them money for a Johannesburg property that they claim I lived in last year. Despite numerous attempts to contact Saya and AFHCO, and various emails I've sent to both explaining that I've never lived in that property, I've gotten no response from either. Today I received an SMS and email from Saya stating that I have 3 days to pay or they will proceed with an ITC listing process.