Vodacon poor service

On the 19th of February I gave notice on my Vodacom contract I ********** , on the 20th of March I contact the Vodacom call center and was advised that my notice was not captured or updated on the system (Reference 1/ ********** 163861), they billed me for an additional month. During this call for the 20th of March the consultant informed me that he will refer this to the account department in order to reverse the last bill. Today (10/6/2019) I received a email from Hammon Pole Attorneys (Contact Betsie Abrie) informing me that my account was handed over and that a amount of R606.27 is payable. I phoned Vodacom and was referred from border to post (Last2x persons spoken to was Thuli and Prince). Prince advised me that he needs to transfer my call and that I need request that the last amount should be revoked, I was then informed that they can not help me as my number was converted to a pre-paid. The system then converted to a African language which I could not understand.