Multichoice contradicts own statements and balances

Multichoice claims they transferred my credit balance on my box office account to my dstv account. Yet not a single statement shows it. They tell me on a certain month my balance was X and because of the credit it went to Y. Yet, I sent them their own statements to show them for many, many months before that i always had the Y credit which their statements reflect. they keep promising to send me statements highlighting the transfer of credit, yet it never shows. they want to talk to me on the phone and try and explain it yet they cant show it on statements. They claim they cant see far back due to new system but could tell me of a balance in 2015 - so how can they not see far back? Not one statement reflects the credit or the balance they claim i had. All their statements they emailed me in fact shows the balance i claim i have and nowhere does it shows the box office credit they claim they made - not 6 months before or after they claim it was done