Pathetic communication between different Cell C departments.

After many email sending my proof of payments and my correspondence with Cell C regarding my so called account that is in arrears. After many emails and correspondence between me and different departments of Cell C, I received two mails as well as a sms where they apologize for the inconvenience and that my account is not in arrears and number in question is fully paid and now a pre paid number after I gave my 1months notice. Now all of a sudden different collection departments phoning me regarding this same issue that was solved two month ago! VVM and Cell C collections. What is wrong with this company! If Cell C blacklist my name believe me there will be trouble! I have all my proof! And why must I send it again if this is resolved two months ago already! What a pathetic company and service! My side is clean and I did everything I could. Why must I fight again for something that was not my mistake but a mistake from there side! I would like to speak to someone competent who are willing to assist me and finally sort this problem! I know I am not in arrears and have proof of that from Cell C....Why did they not communicate this through to the collection departments! And why are there two different departments phoning me and asking for more proof!