Upset customer - ADT security services

I have had the worst experience as a reasonably new client of Fidelity ADT. However, the points listed below justify my opening sentence:

* From the initial signing of the contract during the sales meeting, I got informed I was purchasing a new system, which was a lie as the unit received was used, evidenced by the condition of the keypad and the system linked to another household. (Misleading)

* I was upset at the item's condition; however, I was okay as it was working. However, a few weeks later, the device's battery began not to work, i.e., it no longer charged.

* I contacted ADT, who informed me it was due to load-shedding; their reason was always load-shedding, though it was a two-week-old device.

* They sent a technician to see and resolve the issue, and he replaced the faulty battery with a "new" one. Unfortunately, after replacing it, the matter reoccurred; battery life also lasted for about two to three weeks.

* I have sent an email to ADT and logged a few calls with them, and to the technician, to no avail. You either get an automated response or a response, "I will escalate the matter to management".

* My device, which I have settled (paid off), has been off for over a month. (Not working)

I am distraught (understatement) about the product and service received. The above comes from an organization that prides itself on being a "world-class security solution for your home."

I hope the matter gets addressed ASAP; if not, I would like a full refund and the cost incurred for telephone expenses and fuel to avail myself at home at inconvenient multiple times.