Bad, bad service

My phone was ****** on the 27th of July 2020, I reported it and ask Vodacom to blacklist the phone but there are still recharges on my account for airtime every month and now they are telling me that the handset was not insured. I emailed them all the proof of my monthly installments a few weeks ago already, I forwarded the same email twice already and still no reply. Now they keep on telling me the phone hasn't been used but I get billed every single month!