BILLED FOR INSTALLATION ALREADY PAID FOR

I had requested that an additional PIR be installed at my home in June 2015. I paid for the installation via EFT. After weeks of back and forth, and having to send the proof of payment umpteen times, the installation was eventually completed in October 2015. I have now once again been debited with the same amount, so I have essentially paid twice for this installation. I need this rectified as soon as possible. I have yet again sent through the proof of payment, but have received no feedback from ADT - whether my account will be credited or whether I will receive a refund.<br> <br>