Charged for services not rendered

I requested a de/re installation of my device from my old car to the new one. Technicians came to do the de-installation and I was thereafter charged for both and funds debited from my account. I further scheduled a re-installation however Technicians didn't show up and no communication was made. I tried calling the call center on the day the re-installation was suppose to happen and the day after but no respsonse, infact on the day of the installation I had the phone hung up on my ear twice. What repulses me is that when an agent called me to arrange for payment I told her that I want the funds to be debited from my account on the last day of September she then told me they were already busy finding out if I have money on my account so they can debit meaning the seeking consent and arrangement exercise was just to fool me. I asked the agent what guarantee do I have that they will still install the device now that money has already been debited her response was I must take her word for it. Now money was debited but I haven't received the service.