Worst provider ever

In 2016 i took a wifi router contract with vodacom my 24 months passed and the contract expired according to an agent the contract will remain a month to month contract after the contract expired i never knew this so it went into arrear plus no one called to confirm why then 3 or more months past then i found out i was in arrears i paid the arrears and i called them about 4 times to ensure it cancelled and paid then i went on with my life then i went to apply for a new phone with CellC then they said i have arrears with vodacom that i paid last years up i went back to vodacom paid the R11 arrears and requested a paid up letter this time i requested the letter on monday then by wednesday i didnt receive it so i called again they said EOD friday today is friday i called again and i didnt receive anything they said again EOD friday well its almost midnight. I am not happy with the fact that i paid the account up more than a year ago and i took a look at my credit score well this affected it for the last year i want this fixed and i want resolved now and i want my paid up letter asap because this is causing a lot of inconvenience.