INVOICE CHARGE REVERSAL FAI

ADT invoiced me for the security upgrades done in Oct 2014. The invoice included charges for work that was ultimately not done. After many e-mails going back and forth, they agreed to REVERSE these charges. I've been in communication with a lady called Sebenzile in the accounts department who promises to call me back in 2hrs after effecting the reversal. She has done this from Nov 2014, and last week she offered the same whilst sounding all sincere. Furthermore, my monthly ADT account has been way higher than the original agreement. Something is cooking in that Accounts Department with my account. PLEASE HELP, ADT not the best service provider right now!