No response to query for over 3 months now

During April 2015 I mistakenly made a second payment to ADT, I use to have two premises with ADT but due to incredibly bad service I cancelled the one property and will be cancelling the second property as soon as my contract lapses, I have been dealing with their credit control and explained that due to them cancelling the response to my one property without advising me I was cancelling the contract. Since the over payment I have spoken to and emailed Violla on [Email Removed] from the 23 April 2015 who eventually referred me to Chesiwa who undertook to come back to me in a day as his Supervisor a Maharaj was not in, I then called again but could not get hold of this Chesiwa or Maharaj who I left a message to call me, with no surprise this has never happened. On the 18 June I managed to get hold of Chesiwa who undertook to come back to me on 20 June as Maharaj was again not available, which has still not happened. It would seems that ADT is just too busy to bother coming back to its clients.