Vodacom is affecting my living conditions

I took a contract with Vodacom back in 2018 for a mobile data device mainly to contribute to my credit score as I was 22 years old at the time. When the contract ended I went to a vodacom store to cancel and to make sure I didn't owe them anything . Early this year I app**** for flat with a local rental agency , obviously they do a standard credit check . They contacted me and said that I was flagged by vodacom as I had outstanding fees . I contacted them and asked why this was not brought up when I cancelled my contract initially, and why I was not emailed or phoned by any of their accounts staff to inform me of this for a whole year . I make the payment of R 1239.50 on the 14/02/2020 and they ensure me they will take me off ITC and that my name will be clean .Fast forward to the beginning of this month of November 2020, I apply for a new apartment with a different rental agency and they tell me that Vodacom has flagged me once again . Because of their incompetence they are now affecting my life .. I am still a Vodacom user , and I have no idea why ?!?! Its absolutely pathetic. Please people stay away from Vodacom