INVALID LETTER OF DEMAND

ADT can not do their own internal admin and do not respond to any correspondence in any way. We had a property in Pretoria that we sold. The new owners arranged with ADT to transfer the contract(subscription) to them as they occupied the house now. ADT Head Office phoned me on 30 December 2014 requesting that I send an email to Me Combrink confirming that the new occupiers can take over the subscription. This I did immediately upon the request. I have all the emails I sent as well as the read acknowledgements from ADT. Last night however I receive a threatening Letter of Demand from ADT to pay for the subscription. The alarm was not provided by ADT. I bought the alarm from an independent installer, so there are no alarm fees payable to ADT. This is absolutely ridiculous and to date I have not received any correspondence back from ADT, although they ready all my emails. Why should I pay for a service not provided to me when the new owners of the property already paid for the service for the period from the same address and radio. Get your act together and resolve this matter today still!!!!!