Arrears

I just received an email from your company showing "my ***, your ***" dated 7th October 2020 I am told that my account from Vodacom of which I don't know about it handed to your company because it has arrears of R156 due to that I breached a contract by defaulting paying my account, Vodacom sorted their mistake, because it was not my mistake 14 September 2020, now you telling me I must pay R156 for arrears I don't know about, and you threatening me if I don't pay it will go to credit beareu for what?