Not an agent

On the 24 August 2018 received a sms tell me that I have to pay R919.04 .I called them back and tell them that I'm not their agent and I didn't request the stock they send me,they gave me some number to call 1 of their agent she will come pick them up.UNfortunately I couldn't get that agent .I call them back and tell them. The girl I was talking with she promised to send she will send someone to come pick up,but waited nothing happened .they keep on sending me massages that told me that I'm in arrears .I called again around November they told me that they launched a complain and they gonna send someone to fetch them .the only thing I receive is the sms of up going amount of money .they not even willing to help solve the problem ,the only thing I have it empty promises from them.guys please help