Unbelievable bad service

Our company cancelled our contract with ADT almost a year ago. In February we receive an sms from Ms Selone stating that we still have an overdue account and that will be handed over to the legal department and will be blacklisted if we do not pay. First of our account with ADT was via debit order each month and we did pay up until the last day, but we paid it anyway on the 03/03/2015 and sent the proof of payment to her e-mail address. Today they called the owner of the business stating that the account has still not been paid. I called back and asked to speak to Ms Selone, I told her to please go check her mails from the 3rd of March 2015, and she admitted that she has received the e-mail. She didn't apologize for her neglegt to close the account nothing.<br> <br> This was a very bad experience and I warn anyone that uses ADT security if they can't even do a simple thing like to allocate a payment to a cancelled contract how will they protect you in your time of need.